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Aqua Puttana 12-29-2013 04:03 PM

Some 2004 Espar Heater Notes
5 Attachment(s)
This is not really a Write-up, but not just a question either so I'll include it in Database for any information it provides. There are many other references and tips found in the Database section too.

See also The Espar Files
bc339 Bruce did a great job compiling information.

Espar parts which are verified correct for my 2004 Booster Heater:
(Kubbie's 2006 is the same as my 2004.)
Burner with integral fuel pipe = Burner 25 1922 10 00 00 (no fuel strainer needed)
Gasket and Seal 20 1752 99 01 01 Newer Number = 20.1820.99.0001.0A (All D5 units)
Glow Plug (with integral leads) 25 2106 01 10 00 aka 25.2106.01.1000 aka 25.2106.01.1000.2F
Blower Assembly 12V/D5W SC 25 1922 99 16 00
Exhaust Tube = 24mm inside diameter. Approx 10" L. needed to muffler


Originally Posted by Type2Teach (Post 283253)
After trying to order parts from esparparts.com online and having Paul call me, I would suggest that anyone ordering from them for the first time should call and order over the phone. Saves alot of confusion.

The Varnish Sniffers across the pond have been busy revealing interesting information about the Espar heaters since I last visited their site.
Thanks goes to Seans for the update. :thumbup:


Originally Posted by seans (Post 419284)
Hi Vic!

The British site which is a growing fountain of Espar information has more photos of a teardown and cutaways:

http://www.letonkinoisvarnish.uk/Ebe...r_Intro_1.html - "home page"
http://www.letonkinoisvarnish.uk/Burner.html - cutaway photos of a different model burner
http://www.letonkinoisvarnish.uk/Hyd...Service_1.html - shows cutout of burner showing screen deep inside.


Seans also has some great info for repairing the blower motor. :thumbup:

Per Espar Literature
"The Hydronic D5 generates 17,500 BTU of heat for quickly pre- heating your trucks"

"The heaters regulate the coolant temperature between a low of 149F (65C) and a high
of 167F (75C) by automatically cycling the heater between the heat levels to maintain
high heat temperature."
The Sprinter Espar seems to control to a bit higher temperature range.

Note: One expert I've communicated with warned that Bio-fuel is a problem with the Espar heaters. He even cautions against 5% and suggests installing a "Day Tank" and running the heaters on Kerosene. I can't disagree, but installing a day tank with easy fill capability is likely easier said than done. He mentioned that a coffee colored residue which is harder to clean than the normal black soot is one evidence of bio-fuel rlated problems.
Added: I was recently made aware that the NAS aka NAFTA T1N models have the fuel fill body metal chamber on the passenger side. That area may provide a place to add a fill port to an Espar day tank mounted under the Sprinter.

Some knowledgeable Espar folks.
Ray - Espar of Michigan aka esparparts.com

Guy - Boat Electric - Seattle, WA

Be aware that there is some misleading information found in some Espar Sprinter specifc PDF manuals. (See post #5 below.)

My 2004 Booster Heater label information is as follows.


25 2343
00 0023
43W 12 volt
5.0 KW
Max 2.5 bar
ZGS 001

3/4" coolant hose in and out. (Inlet is on outside corner.)
The Espar D5W
Minimum water flow through the heater = 250 l/h. (Approx. 1 gpm)

Booster vs Aux Note.
My Aux style 2006 Espar is a Espar D5WS which has 2 each electrical connectors. The same main connector as my 2004 D5WZ Booster with a 2nd smaller connector on a pigtail.

My Espar doesn't have a glow plug strainer and seals at all. It has a integral fuel pipe built into the burner assembly. The glow plug fits into a "D" shaped chamber which has a screened "window" out into an "intermediate" burner chamber. (Don't dig the screen out if you clean the glow plug chamber. In fact, don't use any digging tools near the screen especially above it where the fuel weeps in.)

Attachment 56481

Attachment 56484

Attachment 56485

Integral Pipe Burner Style notes.

There is a similar looking D5 burner with no integral fuel pipe that will not work. The no fuel pipe burner part number 25.2216.10.0000 aka 25 2149 10 00 02 won't work if the integral fuel pipe no fuel strainer burner is what you have, so don't be fooled.

Burner with integral fuel pipe - no fuel strainer = Burner 25 1922 10 00 00 (fits model 25 2009 05 and 25 2031 05 among others.) Esparparts.com

The gasket and seal kit appears standard for D5 units.
Gasket and Seal
#9 Seal 20 1752 99 01 01
Newer Number = 20.1820.99.0001.0A

Note that some D5 Espar heaters have a fuel strainer in an external style glow plug holder. The fuel pipe is integral to that glow plug holder. Mine has the burner tube with integral fuel pipe.

Early "S" Heaters

4a = Burner 25 1922 10 00 00 fits model 25 2009 05 and 25 2031 05 among others. (My 2004 with built in fuel pipe.) (Use the Espar model number if they don't like the Sprinter OEM model information.)

11a = Glow Plug 25 2106 01 10 00 aka 25.2106.01.1000 with integral leads. (My 2004.)

4 = Burner h5 2219 Part # 25.2216.10.0000 Part stamped 25 2149 10 00 02
(Fuel Strainer type burner. No integral fuel pipe.)


Attachment 56616

This youtube shows a unit with the integral fuel pipe. The unit shown has the lug type glow plug, not the glow plug with integral leads as mine has. My Espar has Torx fasteners.


This youtube shows the newer style fuel strainer in an Airtronic.


I've removed and taken apart my heater quite a few times now. I cleaned different things as I progressed. I finally got it to operate for a few times, but it won't start first time reliably. Once it fires it runs until the engine is up to temperature.

The heater burner chamber was so clean from the beginning, the air section like new, and the muffler/pipe is pristine, so I don't think this unit has ever operated since new.

Some things that I've learned.

The fuel doesn't squirt in under pressure. It more flows in like a traditional kerosene pot burner stove with a carburetor. In my old style unit the metal screen enters through a slot to provide a "wick" which lets fuel seep in from the fuel pipe deeper down in the glow plug chamber. Until cleaning those weep holes with a dental pick and shoving a thin wire right down the fuel pipe I didn't get the heater to actually fire, it just produced white smoke. When I stuck the wire down the fuel pipe it did seem to hit some resistance at first so that pipe may have been restricted.

What I learned after it fired.
The earlier times that I thought it was firing it was just burning fuel in the glow plug chamber which produced white smoke and did not ignite the main chamber. Actually evaporating might be a better term than "burning".

The faulty operation sequence as I recall it.
The engine noise at idle makes it hard to be certain of some noises. After starting the engine the Espar combustion fan would cycle for a quick ramp up. After a short fan run cycle to purge the combustion chamber the fuel would pulse in. The heater would begin pouring out white smoke. I thought that meant it was firing because the combustion fan would ramp up. After ramp up I'd see even more white smoke. Then the fuel pump would stop, the fan would ramp down, raw diesel fuel would drip out the exhaust (I later learned that my muffler packing was soaked with fuel.), the fan would run a while (combustion chamber purge) and then slow down. After (if?) the first start fails, the blower runs on a low speed into a 2nd start attempt. If the 2nd start fails, the blower continues to run through a standard cooldown cycle and then locks out for no more attempts until a power down reset.

Each failed ignition attempt dumps about 1 1/2 teaspoons of unburned (raw) diesel into the combustion chamber. No ignition at all = x2 start attempts = approx. 3 teaspoons of fuel. The combustion fan carries that fuel to the exhaust system. Once the muffler stuffing is saturated the fuel will spill out from the exhaust system.

I learned that when the heater actually fires off there was just a little white smoke and then the Espar would begin to roar. You will recognize the roar as opposed to just the fan ramping up. It sounds like a low rubble not just a whine. The whine is just the fan turning up to very high speed. For each start attempt the fan will run and the fuel pumps until the flame sensor (actually temperature) sensor kicks into the circuit and realizes that there is no main flame (no temperature rise). It then stops the fuel and the fan ramps back down, but not shut the fan down right away. As I said, the white smoke I saw is just the glow plug chamber fuel burning (evaporating?) and not actually igniting the main burner.

Firing correctly = A little white smoke then No Smoke. Not enough air = Black smoke. Unburned fuel = White smoke.

I plan to open the heater again and try to clean the glow plug chamber holes a bit better. I think that may help to get more reliable starts. Anyone have any input or experience for this?

Edit: I did open up the holes more. That made my heater not fire at all. It just made it a wonderful smoke machine.

The screen in the "D" shaped glow plug chamber is critical to the main burner ignition. I have dug out and uncovered a slot just above the screened 3/16" hole window. My observation is that the screen covers the little 3/16" window hole (the screen needs to only surround it), but it also continues up into the main fuel chamber. The screen then acts like a kerosene lamp wick in that the segmented fuel is ignited by the glow plug and the flame travels to the main burner.

The screen does act like a kerosene lantern wick. The "window screen" goes up into the fuel pipe chamber. A regulated fairly tiny amount of fuel weeps down onto the screen where it is "segmented" to be ignited by the glow plug. Once it has ignited, the flame goes out into an inner chamber which is between the center round (combustion air) hole and the "D" shaped glow plug hole. That flame path via the intermediate chamber is what ignites the main burner.

When I probed at my screen "weep holes" (which are actually a slot for the screen) I opened them up too much. With too much fuel leaking into the chamber I think that it is over-whelming my glow plug. It then just creates white smoke and doesn't ignite.

I tried different things to repair the screen and slot with no success. (Success ultimately!!! See post #3.) I have decided to order a new burner and see if that fixes my problems. (about $260) I believe it will. At one point I must have hit close to the correct fuel drip combination with my added screen before I opened the "slot weep holes" too much. The heater was firing off about every other start sequence. Once it fired it ran perfectly. I decided to improve that starting ratio and really messed up the burner. For engine pre-warming use I should have just been happy to monitor that the heater fired up properly.

Some additional glow plug chamber info is here in another thread which I started.

Espar D5 "S" Heater Glow Plug


Espar D5 Fuel Quantity Test

Fuel Quantity Test
The fuel Quantity should be tested if the heater has difficulty
starting or maintaining a flame.

Note: Measure the fuel quantity when the battery is
sufficiently charged. At least 11V and at
most 13V should be applied at the control
unit during measurement.

• Remove metering pump cover in the cases of SC versions.
• Pull the fuel line off the combustion chamber and insert
into a graduated measuring glass
• Switch the heater on, when fuel delivery is uniform
(approximately 40 seconds after switching on), the fuel
line is full and bled.
• Switch heater off
• Empty measuring glass and replace

• Switch heater on
• Fuel delivery stars automatically approximately 40
seconds after switching on
• Hold the graduated measuring glass at the glow pin
height during measurement
• After 90 seconds of fuel delivery, it will shut off
• Switch heater off.
• Read off quantity of fuel delivery in the graduated
measuring glass


Nominal value


Hydronic D5W SC

8.6 cm3 / 90 seconds - Maximum Qty
7.5 cm3 / 90 seconds - Minimum Qty

7.5 ML = approx. 1 1/2 teaspoons

I found that an old Baby Medicine Dosing Spoon worked perfectly to measure the fuel output. The output from my pump was at the 7.5 ML low end of the specification. (Note that the 90 second test includes a combination of low pulse and high pulse pump operation. Low pulse = ignition cycle. High pulse = ramp up until no flame sensor cutoff.)

Attachment 56483

The fuel doesn't "pump" out it more trickles out. You can feel the fuel line pulse as the fuel is "pumped".


Some other 2004 Espar Booster Heater threads which I've posted are here:

Remove Espar Heater from T1N

General Espar Heater Wiring Information

Cabin Fan Resistor Circuits

T1N Booster Heater Wireless Control

Some Misc Information

Espar D5 Heater
5 kW (17,000 BTU/hr) - High
2.4 kW (8,200 BTU/hr) - Low

Approx. 12V Power Consumption

4.16 amps High
1.91 amps Low

Approx. Fuel Consumption (+/- 10%)

0.62 l/hr (0.16 US gal/hr) High
0.27 l/hr (0.08 US gal/hr) Low

0.62L = approx. 2.620587 cups

As an aside.
Using 5KW as the +/- heat rating.
It would take approx. 40 amps at 120 volts or 400 amps at 12 volts to produce that amount of heat. I believe that helps to illustrate why diesel heaters are used in vehicles and not electric heaters.

Aqua Puttana 01-03-2014 01:46 PM

Re: Some 2004 Espar Heater Notes
5 Attachment(s)
DIY Espar Reset

Apparently a reset can be accomplished without a scan tool or control head communication. Thanks goes to SkyGypsy. :thumbup:


Originally Posted by SkyGypsy (Post 597503)
If the unit doesn't start, then you can clear and reset the unit by powering it up, then pulling the fuses underneath the driver seat. I have done this several times and gone from no response to startup in moments.

I have done a full overhaul on my unit. I should post a write up on it. I have the factory manual, maybe I will post it on my website for others to download.

I have not tried the above.
I assume you pull the 25 and 10 amp fuses labelled for the heater.


Originally Posted by Aqua Puttana (Post 708563)
It just occurred to me for the BOOSTER Heater. The engine may need definitely needs to be running with the bowtie (bacon) switch activated before pulling the fuses (25 and 10 amp) under the driver seat for the reset attempt. Until the conditions for enable are in place (engine running, bowtie switch on), pulling and replacing the fuses may will not work for reset.

:2cents: vic


Burner Info in this post.

I'm looking for pricing on a new burner. I've dug up some information so I figured I'd update. My searching is specific for the early model year NAFTA or NAS 2004 Sprinter.

By Kubbie's model, the integral fuel pipe/"D" glow plug chamber carried on for Sprinters into 2006. I presume that at some point the Sprinter heaters have upgraded to the newer style fuel strainer glow plug ignition system.

Espar of Michigan Sprinter Type Parts


Attachment 56623

I've read that the OEM Sprinter heaters are not always supported by Espar. That is apparently not true.


This is the 2004 Sprinter heater style generic burner with Integral Fuel Pipe and "D" Glow Plug Chamber.

Burner with integral fuel pipe
Burner 25 1922 10 00 00 fits model 25 2009 05 and 25 2031 05 among others. (Looking good for my 2004. 100% certain that it is correct with integral fuel pipe.)
Another possible part number.
Eberspacher D5WSC 12v Hydronic Water Heater Burner with integral fuel pipe
Manuf. Number 252069100100 (or 25 2069 10 0100 ??)
Claimed to fit Hydronic D5 models 25 2098 05 0000, 25 2099 05 0000, 25 2083 05 0000, 25 1975 05 0000, 25 1920 05 0000 D5W

Gasket/Seal Set (19/13 Dichtungen)

New Description
Blower/Burner Seals ($15.90)

2 pieces in this part. There is a fairly thick paper gasket for the burner to Fan/Control Module Housing Assembly face connection and a graphited circular seal for the Burner to Water Jacket Combustion Chamber. This part is common to all D5 burners as far as I can determine. Approx. $20 at this writing.

Attachment 57391

It does not include the O-ring seal for the water jacket.
O-Ring 74x3mm D4/D5 Heat Exchanger
O-Ring for heat exchanger, Old P/N:320.75.104

(The O-ring is not needed for a burner cleaning or burner replacement. The 20.1820.99.0001.0A set is all that is needed for the burner R&R.)

The integral fuel pipe style unit glow plug can also be different. Mine has an integral cable assembly. The newer style fuel strainer type burner glow plug has terminal posts.
Glow Plug 25 2106 01 10 00 aka 25.2106.01.1000 with integral leads.

Edit: I ordered a 25.2216.10.0000 burner. 25.2216.10.0000.2C label on the box. The part inside box had 25 2149 10 00 02 stamped into the face. It does not have the integral fuel pipe at all. It uses the fuel strainer style. It is the reduced step fuel screen. There is also a no step straight strainer. So 25.2216.10.0000 aka 25 2149 10 00 02 is NOT the correct burner if you have the integral fuel pipe. Apparently the box number and metal stamped burner face number are equivalent parts.

Note: The original design of the integral fuel pipe burner included that the screen "wick" went over the 3/16" hole. One Espar tech commented that he had learned to poke that screen open so that it looks like the pictures below. He said with the screen across the hole the screen needs to be cleaned every couple years. You get longer service intervals with the screen not being across the hole.

"Wrong" Burner At least for my 2004. Fuel Strainer type, no integral fuel pipe.
I include this for the "D" chamber pictures.

Attachment 56829

Attachment 56830

As a reminder, this is what the burner with integral fuel pipe looks like. The pipe enters the face of the burner near the "D" glow plug chamber and continues through to the back.
25 1922 10 00 00

Attachment 56950

On another note.

Mercedes Benz recommends operating the Espar Booster and Aux Diesel Fired Heaters once per month to keep them operating properly. The U.S. government then mandated a temperature lockout which keeps the heater from operating until the ambient temperature is below 39F. :rolleyes:

Edit: It seems that MB/U.S. Government didn't do that to owners until NAS 2010. Thanks goes to glas1700 and K-9 Sprinter for the info. :thumbup:


Originally Posted by glas1700 (Post 275583)
I think you said that you have an 06 van. If so and you have the MB installed ESPAR, it should start and run in any temperature as long as the engine coolant isn't up to normal operating temperature. ...


Originally Posted by K-9 SPRINTER (Post 275592)
yep ... temp control of above 39 degrees started in 2010


Originally Posted by Missouri Blue (Post 345408)
Here are Thermo King's part numbers:

gaskets: 83-360 (@ $19) (espar: 201820990001)
o-ring: 83-319 (@$4) (espar: 221000700002)
glow pin:84-1059 (@$130) (espar: 252106011000)

I did not need a glow pin/plug but had them look up the part # anyway. Also, I will not be using the o-ring either.

Aqua Puttana 01-17-2014 01:31 PM

Re: Some 2004 Espar Heater Notes
2 Attachment(s)
REST Pre-heat Modification and MB Wire Colors are in this post.

My Espar heater has been operating for about a week now the entire season into the next year. I was able to repair the fuel flow control from the main fuel pipe to the glow plug chamber by using some materials I had on hand. One of which is a nickel mesh screen. Based upon the repair I can say absolutely that the OEM screen/slot arrangement in the glow plug chamber does act like a "wick".

The metering of fuel "wicked" into the glow plug chamber is a critical parameter to the main burner igniting. Too little flow and it won't fire reliably. Too much and it will just throw out white smoke and won't fire at all. During burner cleaning never dig at the screen area at all. I recommend cleaning the glowplug aka glowpin "D" chamber with carburetor cleaner and maybe a light touch with a small brass 22 caliber bore brush. I suggest that the last stages of cleaning should include spraying some carb cleaner into the fuel pipe to flush things through. Perhaps including a thin wire poke into the fuel tube before the last flush.

I will not reveal my burner screen repair methods because, although my repair is very effective and safe, repairing/modifying a burner is probably not the best route for most people. I am having quite a time identifying the Espar part number for the D5 integral fuel pipe type burner. I plan to replace my repaired burner when, if??... I ever get the correct part number. Edit: Found it! Burner 25 1922 10 00 00 . It fits model 25 2009 05 and 25 2031 among others.

My dash switch and diode modification combined with the REST feature works to give me 30 minutes run time with the cabin fan on low without the engine running. At the end of the 30 minute run time the Espar cycles through a normal programmed shutdown. Operating the REST (Aux Electric Coolant Pump on) without the added heater dash switch enabled doesn't affect normal REST operation. The switch/diode/REST will give you 30 minutes of engine pre-warm time which I have found adequate to pre-heat the engine..

Attachment 64463


Originally Posted by Aqua Puttana (Post 341811)
REST/Booster Engine Pre-heat with DPDT Switch Modification

My original circuit using a switch and a diode for REST engine pre-heat works, but it has some flaws in that it can backfeed 12 vdc into some other circuits connected to Splice #362. For a basic optioned Sprinter like mine that is not a problem. For Sprinters which have things tagged on to the Optional Equipment Relay it can have some negative effect. (Not necessarily serious, just a nuisance.)

Realizing that, I looked for another option. After a couple different solutions I developed a circuit that uses a common Double Pole Double Throw DPDT switch. This new circuit prevents any 12 vdc backfeeds and should also address the ABS module pre-start check glitch.

Most of the connections are found in the dash area on the ATC Module. It will be necessary to run a 2 conductor cable from the DPDT dash switch to the BK/BL/DG wire Espar Pin #6 at the Booster. That BK/BL/DG wire may be available in the area of the dash to cut and connect. Using the documentation that I have available to me I was not able to determine if that is a practical solution or not.

With the DPDT switch in "Normal" position (as shown) the REST and Booster Heater function per OEM design. With the DPDT switch in "Pre-heat" position REST powers up the DG/RD wire Circulation Pump which also enables the Espar heater. This allows approximately 30 minutes of pre-heat operation until REST times out.

Here is the basic circuit shown on the Booster Heater Diagram.

Attachment 64544

Presently my switch and diode arrangement does what I need for my engine pre-heating. I don't plan to change over to the new design. That said, the newer DPDT switch circuit modification is the better choice.

If anyone has questions please start another thread. That will allow me to move information to here rather than having this thread go too far off topic. vic

P.S. - Some PM's with Mortarsprayer got me back to thinking about this modification.

As an aside.
As I have said before, I don't think that my Espar has ever worked since new. When the heater wouldn't fire I would get raw fuel out the exhaust just before shutdown. When I first got my heater firing reliably I didn't have the exhaust pipe connected. The heater would give a small amount of white smoke and then begin roaring a bit. There was no smoke once the main burner fired.

After operating a few times I connected the exhaust and set the REST timeout in motion. After a bit of warm-up the exhaust began billowing white smoke to the point that I was afraid that the neighbors might call the fire department. Fortunately it was quite windy so the smoke didn't linger much. I knew that the heater was firing smokeless without the muffler. The smoke was from all the fuel that was soaked into the muffler sound packing material. I saw no flame at the muffler so it was being evaporated off. The heater is now operating cleanly with no smoke. The exhaust system is fully connected.

I have been using the heater daily to assure it is OK. It is actually kinda nice to have it operating.


20141129 Edit: These Sprinter wire colors and function are deciphered from a few different technical sources and schematics. You will not likely find this info in many places. MB doesn't make it easy to track down using just their Service Manual schematics. The MB OEM controls are a step child to Espar that they have no interest in.

Sprinter OEM Espar Plug Info

Chamber (Pin) - Cross section/Colour - Function

Pin #1 - 1,5 red - plus supply, terminal +30 Sprinter = Orange? (Red/? - Heavy Wire) - All (8W-42-11)
Pin #2 - 1,5 brown - minus supply, terminal –31 Sprinter = Brown (Heavy Wire) - All (8W-42-11)
Pin #3 - 0,5 black/red - not in use? Sprinter = Blue/Yellow - Program Timer Only - Fan Stage 1 Relay = REST Low Spd (8W-42-08)
Pin #4 - 0,5 green - plus signal, dosing pump Sprinter = Dark Green - All (8W-42-11)
Pin #5 - 0,5 blue/white - diagnosis Sprinter = Blue/Red - All (8W-42-10)
Pin #6 - 0,5 blue - terminal 15 Sprinter = Blue - Program Timer, Black/Blue/Orange - Except Program Timer (8W-42-10, 8W-42-11)
Pin #7 - 0,5 yellow - D+ dynamo Sprinter = Yellow - Program Timer. Blue - Except Program Timer (8W-42-10)
Pin #8 - 0,5 black/white - not in use?? Sprinter = Blue/Yellow (8W-42-09)
Pin #8 Clarification Note:
Cabin Heater Module aka Program Timer = Circulation Pump Relay - Cabin Heater Module (Relay Block)
REST System aka Except Program Timer = ATC Module - No Relay, Direct (Heater Booster Mode) (8W-42-09)

*The Dash Inset Control aka Program Timer will have a Circulation Pump Relay and a Stage 1 (Low Spd) Fan Relay under the driver seat.
* The Booster Heater aka Except Program Timer doesn't have any related relays under the seat.The ATC module does the logic/control for the Booster Heater/REST pump and fan.


Originally Posted by Aqua Puttana (Post 598971)
Apparently a reset can be accomplished without a scan tool or control head communication. Thanks goes to SkyGypsy. :thumbup:


Originally Posted by SkyGypsy (Post 597503)
If the unit doesn't start, then you can clear and reset the unit by powering it up, then pulling the fuses underneath the driver seat. I have done this several times and gone from no response to startup in moments.

I have done a full overhaul on my unit. I should post a write up on it. I have the factory manual, maybe I will post it on my website for others to download.

I have not tried the above. It does work.


autostaretx 01-17-2014 03:28 PM

Re: Some 2004 Espar Heater Notes
Just for an amusing datum:

8.6 cm3 / 90 seconds - Maximum Qty
7.5 cm3 / 90 seconds - Minimum Qty
7.5 ML = approx. 1 1/2 teaspoons
The 7.5 cm3 (or milliliter) in 90 seconds means that it uses 300 ml per hour ... think of it as a third of a quart.


Aqua Puttana 01-18-2014 05:27 PM

Re: Some 2004 Espar Heater Notes
3 Attachment(s)
In trying to track down the Burner with integral fuel pipe part number I have learned a bit more about my Sprinter Espar heater so I figured I would share.

Be aware that there can be some misleading information found in many of the Espar Sprinter specifc PDF manuals.

Here is the most inclusive Sprinter specific PDF that I have found. It shows parts breakdown for both styles of glow plug/burner which is either the fuel strainer type GP or the integral fuel pipe burner without strainer.

This link allows you to view the file. I won't download this PDF because I don't know what other files ebookbrowse.net may include.

Some ebookbrowse mixed review is here.

An Espar "All-in-one" Manual is here.

Reference this parts breakdown from Espar parts if you have the burner with integral fuel pipe. (My 2004 Heater doesn't have a lug on the glow plug as shown there. The wire is integral.)


Perhaps use Model # 25 2823 25 0500 (12V) when asked (if you have burner with integral fuel pipe).

25 2091 05 00 00 HYDRONIC D 5 W S, 12 Volt

Attachment 56965

Burner with integral fuel pipe

Burner 25 1922 10 00 00 fits model 25 2009 05 and 25 2031 05 among others. (Looking good for my 2004. 99.9% 100% certain that it is correct with integral fuel pipe.)
Attachment 56966

Glow Plug 25 2106 01 10 00 aka 25.2106.01.1000 with integral leads.
Attachment 56967

Some other "Sprinter Specific" manuals with various info are below. Be careful of using specific parts info in these.

Sprinter Specific PDF for T1N (Parts listed often do not seem specific to my 2004. - For example in this manual - The listed 25 2216 10 0000/stamped 25 2149 10 00 02 Burner has no integral fuel pipe - as the picture shows correctly. BUT the glow plug would need a fuel strainer - the strainer is not shown in the picture so that is incorrect. My 2004 has no fuel strainer.)
Sprinter Specific PDF which includes my 2004 Espar 25 2343 mentioned by MB label model number. (AIRTRONIC info. Some info is similar to Hydronic.)
Srpinter Specific PDF which also includes Espar 25 2343 by model number. (Parts info is AIRTRONIC only)

If a fuel strainer is needed be aware that there is a stepped strainer w/ O-rings, and a straight style.

Step Type = Eberspacher D4W D5W Glow Pin Screen kit (25.2121.99.0113 or 20 1752 99 01 02)

IF there is a strainer, based upon what appears to be the standard burner style, the Stepped Fuel Strainer or atomizing screen is listed with the 25.2216.10.0000 aka 25 2149 10 00 02 burner (with no integral fuel pipe).


Edit: Added parts verification.

Espar Model #25 1988 05 00 00 Hydronic D5W Z - 12 Volt has basic parts similar to my 2004.

Burner with Integral Fuel Pipe 25 1922 10 00 00
Model 25 1988, 25 2009 05, 25 2031 05 , 25 2100

Current link with 3 pictures for verification on the burner style.

As an aside.
This blower fits the burner with integral fuel pipe.
Blower 12V/D5W SC ; 25 1922 99 16 00

Aqua Puttana 01-19-2014 04:33 PM

Re: Some 2004 Espar Heater Notes
5 Attachment(s)
I believe that now I have enough information to end my recent obsession with all things Espar in my 2004. (Just my latest obsession of many?)

The Booster heater is working fine. It is wired to pre-heat the engine. I know what specific burner part number will work.

There was one site that I found which seems to have really good information for the 2004 year range Espar heaters. Unfortunately it is in German and I'm not fluent at all. It does have some great pictures for showing the differences between the non-fuel strainer burner with integral fuel pipe (as I have) and the similar, but quite different design fuel strainer style burner.

I've since learned that Google translate does a rather quick and good job for segments of the German text.

This is the blower assembly with integral fuel pipe. (Similar to my 2004.)

Note the Ignition Air Duct or Channel. On my heater that was completely blocked. It almost seemed like a compound rather than just dirt. That might explain that my heater is in such good condition by having not operated since new. That air duct is critical to igniting the heater. In hindsight, I should have just cleared that duct, cleaned the burner "D" glow chamber with carburetor cleaner (as opposed to digging at the soot/carbon build-up with picking tools - screwing up the screen), and lastly run a fine wire into the fuel pipe with a carb cleaner flush. I'm convinced that would have restored my heater to operation. I base that on the fact that, except repairing the self-inflicted damage to my burner screen "wick", all that I did was to clean my heater fuel and air passages for the heater to work properly.

Attachment 56982

The Burner with Integral Fuel Pipe

Note that the fuel pipe is sandwiched between the blower and burner faces and recesses into the Blower Fuel Pipe Channel shown above.

Attachment 56983

The Fuel Pipe Glow Plug Holder Assembly.

The fuel pipe comes up on the opposite side of the blower assembly as compared to the integral fuel pipe burner style. The fuel pipe is not sandwiched between the blower face and burner face.

It also includes a cylindrical Fuel Strainer assembly aka Fuel Screen aka Glow Pin Screen aka Atomizing Screen.

Attachment 56984

The Strainer Type Blower Assembly. Note the Ignition Air Duct which is similar design to mine that I found plugged.

Attachment 56985

The Fuel Strainer Type Burner Assembly. The 2 ea. green O-rings seal the Fuel Strainer. This uses the "stepped" strainer style. The "D" Glow Pin Chamber also includes a Screen "Wick" even with the Fuel Strainer.

Attachment 56986

A note for cleaning the Fuel Strainer type burner.

The back curved walls area of my integral fuel pipe Burner Burner 25 1922 10 00 00 "D" shaped glow pin chamber is a solid piece. Based upon visual inspection the brand new Fuel Strainer type Burner 25.2216.10.0000 aka stamped 25 2149 10 00 02 also has a solid back curved wall. I inspected the brand new Fuel Strainer glow plug chamber. Unfortunately I can't get a good picture inside so I'll describe it as best I can.

Refer to the 2nd burner picture in post #2 above for an idea of the screen and 3/16" hole position.

The Fuel Strainer burner is non-magnetic and appears to be stainless steel. The back curved walls area of the "D" glow pin chamber is solid. The flat wall has a screen embedded to it on the inside (in the glow pin chamber). An approximately 3/16" hole is in the flat wall out into an intermediate chamber. The screen surrounds that hole, but doesn't cover it. The screen disappears into a slot at the top of the "D" chamber flat wall. There are no other holes which I can see other than the tightly filled screen slot and 3/16" hole out to the intermediate chamber.

My cleaning suggestion applies to the Fuel Strainer burner the same as the integral fuel pipe style. It is best to rely on solvents like carburetor cleaner and avoid poking around too much. The screen attached to the wall may need cleaning, but you don't want to disturb it too much.

The two different fuel pipe entries leaves me a bit unsure as to actual primary ignition. I know that the screen/slot "wick" design is critical for both burner styles. It is interesting that the integral fuel pipe disappears behind the "D" chamber at the rear in contrast to the Fuel Strainer fuel pipe metering fuel into the "D" chamber from the front or glow plug end. I'm convinced that the glow plug produced flame ignites the fuel and exits thru the 3/16" hole into the intermediate chamber. The upstream air pressure via the Ignition Air Duct (Kanal) should overcome the larger downstream air opening (less pressure) so that the glow chamber flame moves out into the intermediate burner chamber. That same Ignition Air Duct air flow must also carry the fuel out to the glow plug chamber in any burner which has the Fuel Strainer. The heaters can be mounted in various orientations so the fuel isn't just gravity fed.

Anyway, things need to be clean and open enough, but not open too much, for flow. I know that the screen and slot, the Ignition Air Duct, fuel pipe, strainer, etc. needs to be clean enough for the heater to work.

The German language site is here. My appreciation and thanks goes to the originator. :thumbup::thumbup: (Pretty much for the pictures, because I couldn't decipher the technical language. :rolleyes: )


There are also some motor brush modification pictoral tips here. The pump motor/brushes shown are very similar to the Sprinter motor, but not the pump body that is shown.
(The 2nd time that I changed the brushes on my water pump I used tape style dental floss to hold the brushes away for assembly. Someone on Sprinter-source mentioned that trick. It worked great.)

The Espar heaters are pretty basic as to the mechanicals and theory. I am impressed with the simple, yet effective design. Once the diesel fuel is ignited, the metered fuel flows in kinda like an old kerosene pot stove with a carburetor. Once lit the diesel fuel will continue to burn readily.

I've not had problems with the control. I suspect that the control module is not at all repairable. There have been some pictures of corroded wiring including one in the German site so that condition is worth watching for.

Note: One expert I've communicated with warned that Bio-fuel is a problem with the Espar heaters. He even cautions against 5% and suggests installing a "Day Tank" and running the heaters on Kerosene. I can't disagree, but installing a day tank with easy fill capability is likely easier said than done. He mentioned that a coffee colored residue which is harder to clean than the normal black soot is one evidence of bio-fuel rlated problems.

Fitting a day tank with an external fill capability may be easier than I thought. Opposite the OEM fuel fill (passenger side) there is an identical unused sheetmetal chamber which could be used to install an external day tank fill point.


Aqua Puttana 01-25-2014 01:27 PM

Re: Some 2004 Espar Heater Notes
4 Attachment(s)
A Basic Cleaning Procedure from another thread, and some documentation at the end.


Originally Posted by Aqua Puttana (Post 280057)
To help keep the other thread on track...

I must admit that the heater is nice to have in service. I've been using it to pre-warm the engine and enhance heat output pretty regularly. Now that I have it I would put money and effort into repairs should it go bad.

It wasn't really hard work. The learning process was what took the time. Had I not screwed up my burner screen "wick" I think it would have been easy. But then I wouldn't have learned as much. :idunno:

My recommendation is to first do a good cleaning. You will need the gasket and graphited ring seal. About 20 bucks.

The gasket and seal kit appears standard for D5 units.
Gasket and Seal
#9 Seal 20 1752 99 01 01
Newer Number = 20.1820.99.0001.0A

Attachment 57369

You might get away with reusing the gasket, but it is a gamble.

A 2003 probably has the integral fuel pipe burner so you shouldn't need a fuel strainer on hand.

The video in my Database link and my jumbled meandering notes should give you all that you need.
Some 2004 Espar Heater Notes

The critical path for Espar cleaning off the top of my pointy head.

Disassemble per video. Be careful of the plastic combustion fan. My electrical connector retaining clip broke. It's no big deal as the O-ring seal on the connector is very snug.

Gently check that the combustion blower fan spins freely. Kubbie used a 9 volt battery test. Re-install the 4 corner fan cover bolts to help provide protection from bumping the plastic fan.

Remove the burner tube from the housing and clean the combustion chamber soot.

Use carburetor cleaner or alcohol to clean the glow plug chamber. Gently clean the "D" chamber screen "wick" and slot. If the screen over the 3/16" hole was heavily sooted you might consider poking it to open the hole like the burner I show in my other pictures. The newer burners do not cover the hole with the screen (wick), it just surrounded it.

Run a thin wire down the fuel tube and flush with carb cleaner. I suspect that you will see fluid weep down into the cleaned screen "wick" on the 3/16" hole.

Clean and inspect the glow plug. No need to remove it. It should be straight. I'm told that as they age they often curve which is an indication that they may be getting near the end of service life. It still should be good though. The glow pin can be tested with 12 volts DC, but be aware that the design voltage is less. 8 volts is what I recall so apply voltage and watch for a glow. As soon as you see glow remove the power. Kubbie used a 9 volt battery for a quick test on that too. :thumbup:

Clean any soot from the flame sensor pin in the exhaust chamber. No need to remove that for cleaning either.

Clean the "Ignition Air Duct" (Kanal) in the glow plug area. That supplies combustion air to the glow chamber. It is critical.

If your coolant has been regularly serviced I wouldn't disassemble the coolant shell. If it's not leaking leave it alone.

Re-assemble the Espar after cleaning. (I put a drop of oil on the combustion fan opposite end bearing shaft. I couldn't access the fan end bearing/shaft.)

Check the air supply tube in the vehicle to make sure nothing is blocking the air flow. Some creatures may think of it as home.

Install the heater in the Sprinter. Don't connect the exhaust yet. If the exhaust is plugged at all it could impede starting. Run first without it and then connect it later.

Before re-connecting the fuel line you should do the Fuel Quantity Test. I like the Baby Medicine Spoon, but you can just catch and measure for a little over 1 1/2 teaspoons of fuel after 90 seconds.

Type2teach Joel reminds us to check/clean the electrical connector plug contacts. That is good advice. I always spritz all my connectors with WD-40 before assembly. There may be better products available, but WD-40 is handy and has done well for me.

Install the fuel line and test the heater.

After it operates remember to re-connect the exhaust tube.

I thought I'd be smart and put a thin coat of Never Seize on the thick paper gasket to keep it from sticking. That was not a good idea. The next dis-assembly I found the Never Seize soaked into paper layers and caused a bit of delamination. By using a blade upon dis-assembly I was able to separate and re-use the gasket, but installing it dry is my recommendation.

That's basically it. Good luck. vic

I've read that Espar heaters "Lock out" after some failed start/ignition attempts. I don't find that true with my 2004.


Originally Posted by Kubbie (Post 281025)
Isn't it true that after a number of failure to fire, the Espar locks itself out and needs to be reset with an MB star tool?


Originally Posted by Aqua Puttana (Post 281034)
I've read that. From my research that may be the mode of a native Espar diesel fired heater. I've read that after so many start attempts the native Espar heater locks out and needs to be reset using the proprietary Espar access scan tool. OR maybe the permanent lockouts are related to specific component failures which are monitored by the Espar computer and people assume it has locked out related to a couple start attempts. :idunno:

My experience:
My 2004 heater main burner never fired for the first 6+ years that I owned my van. I tried it more than a few times over the years. Each time the most I would get was white smoke = unburned fuel. The Ignition Air Duct was plugged solid so the main burner never fired. When the button was pushed the red dash LED would light, the heater would try to start two times in succession and then would lock out, but not permanently. After an engine shutdown and restart it would again give two white smoke cycles.

After I cleaned the burner and screwed up the screen "wick" metering into the glow plug chamber I tried many more x2 white smoke cycles. There was never a permanent lockout. The heater runs fine now.

So, my experience shows that the Sprinterized Espar control module doesn't lock out after a failed ignition sequence. The 2 x start tries are allowed and then it prevents any further starts until power off/on. That is not as described for the native Espar control.

This thread has some good info.

Espar Booster Heater Not Starting - Info near Write-up Status

Some Documentation

Attachment 64389

Attachment 64390

Attachment 64391

Aqua Puttana 10-13-2014 02:17 PM

Re: Some 2004 Espar Heater Notes
5 Attachment(s)
Circulation Pump Control Detail and Documentation


Originally Posted by Graphite Dave (Post 331032)
So far the coldest has been 25 degrees. I suspect it will be fine at lower temperatures. I do plan on leaving space under van in my next conversion for a under floor Propex propane heater if I find that necessary.

I will not use an Espar after my 6 months campaign and $1300 cost to fix my original equipment Mercedes supplied Espar water heater. Many visits to Mercedes dealership to finally convince Mercedes that indeed they built my 08 Dodge and it was supplied by Mercedes with a factory installed heater. Became friends with my local Sprinter service adviser as he tried to get support from Mercedes to obtain the software required to troubleshoot the bastardized design. I have nothing but nice comments about how my local advisor doggedly kept trying to get support. He finally succeeded by going through a back door in the Mercedes system. In a way it was quite comical but in other ways it was BS.

If anyone is in the Santa Rosa area and needs Sprinter service, the adviser is Matt and he has your interests in his mind as he tries to support the Sprinter. I will miss the contact and honesty he displays.

I've been firing up my Espar regularly lately to be certain I'm ready for winter pre-heating. While driving the other day I found myself pondering why MB didn't just use the normal integral Espar coolant pump.

I believe I do have one reason for using the OEM pump. The OEM aux coolant pump runs when the van/engine is down speed 100% of the engine operating time. The coolant pump circulates through the EGR and oil cooler. If the engine driven coolant pump isn't up to speed then the EGR and oil cooler probably don't get proper circulation. I think that the MB logic was that we already need an electric coolant pump, why pay any extra for an additional Espar pump?

That may explain why they have a separate pump. It doesn't explain why they also bastardized the Espar control scheme.

:2cents: vic

More Pump Info


Originally Posted by bc339 (Post 124906)
Glad to hear your system is working properly now. This information was copied from the service manual. It should answer your question about the pump operation.

The electric coolant pump is used on all vehicles. The pump is located in the left side of the engine compartment near the battery.
The pump is controlled by the ATC control module and is only operational under the following conditions:
(1) Vehicle speed below 27 Km/h (17 mph).
(2) Coolant temperature above 65 C (150 F) but less than 110 C (230 F).
(3) Any blower speed setting.
(4) Temperature heat setting above the halfway setting (60% heat).
(5) The pump will turn off at speeds above 48 Km/h (30 mph).
(6) The pump will turn off if the coolant temperature rises above 110 C (230 F).


Recently I have unraveled more information regarding the Coolant Circulation Electric Pump.

After looking at the documentation related to the MB Sprinter Aux. Electric Coolant Pump it appeared to me that either the description in the Service Manual or the schematics are wrong. So far the schematics are the most accurate, but maybe not 100%.

The schematics show the Coolant Pump to be basically fed by 12 volt sources which are subject only to the key position There aren't any fancy logic controls shown in the schematics. Maybe those fancier controls are on other MB models? :idunno:

Based upon the thoughts mentioned above, I installed an indicator light to monitor the 12v power to my Electric Circulation Pump. It was fairly easy because my DIY Booster run with diode modification gave me an easy tap point in the fuse holder. My conclusion is that my pump has 12v power subject to the key. In the case of my 2004 with OEM Booster Heater, the circulation pump runs as long as the key is turned on or the engine is started/running.

I've tried many different operating conditions. So far the circulation pump runs 100% the time.


Originally Posted by bc339 (Post 124906)
... This information was copied from the service manual. It should answer your question about the pump operation.

The electric coolant pump is used on all vehicles. The pump is located in the left side of the engine compartment near the battery.

The pump is controlled by the ATC control module and is only operational under the following conditions:

This is what I found with my Booster Heater aka Except Program Timer unmodified OEM controls/Circulation Pump testing.


Originally Posted by Service Manual
(1) Vehicle speed below 27 Km/h (17 mph).

My test light shows that the pump runs 100% of the time.


Originally Posted by Service Manual
(2) Coolant temperature above 65 C (150 F) but less than 110 C (230 F).

Nope. The pump runs 100% of the time.


Originally Posted by Service Manual
(3) Any blower speed setting.

Nope. The pump runs 100% of the time.


Originally Posted by Service Manual
(4) Temperature heat setting above the halfway setting (60% heat).

Nope. The pump runs 100% of the time.


Originally Posted by Service Manual
(5) The pump will turn off at speeds above 48 Km/h (30 mph).

Nope. The pump runs 100% of the time.


Originally Posted by Service Manual
(6) The pump will turn off if the coolant temperature rises above 110 C (230 F).

Unable to test above 230F, but the pump runs 100% of the time..

From my testing so far it appears that the pump running all the time as shown by the Service Manual schematics is the most accurate.

Attachment 64392

Attachment 64545

Attachment 64394

Attachment 64395

As an additional check I removed my DIY Diode Run fuse to test if the Espar Booster would run while the engine was off. I powered the Pin #7 with the DIY SPDT dash switch. The Espar did not respond at all. I set the ATC REST control to enable (DG/RD powered from ATC Pin C1-2 - Circ Pump Running) with the DIY SPDT dash switch still on. The Espar didn't respond at all.

I replaced the DIY Diode Run fuse. The Espar heater fired up.

Basic Conclusions:

The Coolant Circulation Pump runs subject to the key position as shown in the 8W-42- 09 schematic. There is not a circulation pump complex logic control with my Booster Heater option.

The Circulation Pump is not automatically powered up with the Espar Pin #7 enabled. (Espar wouldn't fire with only Pin #7 energized/enabled)

The Circulation Pump is powered by the ATC C1-2 pin DG/RD wire to run during the REST operation. (Splice #362 isn't in the path.)

The wire DG/RD being powered does not backfeed 12v to Espar Pin #6. There must be a blocking diode for the Booster Heater if it is wired as shown in schematic 8W-42-09. The correct control wiring/logic is likely what I show in blue. (There is a note which indicates the Booster Heater does have a diode.)

For the Espar Booster Heater aka Except Program Timer to operate 12v power must be supplied to Espar Pin #6 (enable). For the Espar Booster Heater that 12v is supplied to Espar Pin #6 via Splice #362. Splice #362 also supplies the Circulation Pump. If power to Espar Pin #6 is interrupted the Booster Heater will power off. That is regardless of whether the engine is running or not. That is another fact which supports that the Circulation Pump must be energized 100% of the time for the Booster Heater to operate.

As an aside, Splice #S362 is listed as "Near Circulation Pump Diode" Fig. 18. Under Driver Seat.

Attachment 64396

I haven't located the diode on my 2004 yet. (Edit: Because there isn't one!!! :bash: )

Please note that the above information is derived from testing performed on one OM647 Booster Heater equipped Sprinter and doesn't necessarily apply to the Dash Inset Control aka Program Timer units or other model/optioned Sprinters.


Aqua Puttana 12-16-2014 12:36 PM

Re: Some 2004 Espar Heater Notes
5 Attachment(s)
Some info which may help repairs.


Originally Posted by Aqua Puttana (Post 344503)


Originally Posted by Missouri Blue (Post 344440)
So I've read all the espar threads and decided to take my Espar out to repair it (it has not worked since I've owned the van: 2+ years). A 1"x1" "sharkbite" brass elbow from Home Depot worked perfectly to complete the coolant loop while the espar is out of the Sprinter... no kinks in the hoses and perfect fit in the coolant lines.

Nice to know. :thumbup:

Extended Espar Removal Note:
The Espar coolant hose circuit includes the EGR and oil cooler system for the engine. If the Espar is removed and the vehicle needs to be kept in service then the Espar coolant hoses must be coupled together. The fitting Missouri Blue mentions above sounds perfect.


Originally Posted by Missouri Blue (Post 344440)
1) The espar is in piece and I need some help. I've read about the screen deteriorating in the "D" shaped glow-pin hole. It seems that my screen is gone and the hole is open. Is there only one hole within the "D" shaped chamber or two? The pictures try to show the exposed hole, where only mesh remains stuck to the metal around the hole. Vic do you have any more nickel mesh?

I have more mesh and you are welcome to have some. That said, some of the burners come with the screen wick only surrounding the hole in the D chamber. One Espar expert which I spoke with indicated that he often punches a hole in the screen if one isn't there. Apparently when the screen covers the hole it can soot up sooner. I believe he said that making the hole buys a bit more time between cleanings.


Originally Posted by Missouri Blue (Post 344440)
2) I tested the fan/blower with a 9-volt battery and it worked. I tried to test the glow-pin as well... I hooked the positive to the black wired terminal and the negative to the white. The glow-pin got hot after 10 seconds, but not too hot to touch. Does this indicate that the glow-pin is functioning but just not enough power from the 9v battery or time to bring the glow-pin up to operating temperature? Or is the glow-pin not working as it is supposed to?

The 9 volt battery test just checks basic function. It doesn't have enough power to make the glow pin come up to operating temperature. If it gets warm then the resistance heating element is intact and it should be fine.


Originally Posted by Missouri Blue (Post 344440)
These pictures will probably be meaningless unless you have looked intently at this part of the espar before. Without some frame of reference they are pretty abstract.


Once you see the heater apart in person it does make more sense.

Not that you asked...

I would re-assemble the heater and give it a test. The screen only needs to break the fuel up into small segments to allow the heat of the glow pin to light it off. Further fiddling with the screen may create more issues than it resolves.


Photos courtesy of Missouri Blue

The "D" chamber with screen.

Attachment 64704

Attachment 64705

Attachment 64706

This is the connector for the Espar internals. (Control Module, Fan, Glow Pin, Flame verification, Hi Temp Limit, maybe others.)

Attachment 64707

Attachment 64709

Aqua Puttana 01-07-2015 12:36 PM

Re: Some 2004 Espar Heater Notes
Mortorsprayer gives a nice overview of a jumper test for the electric coolant pump. Thanks goes to Nolan. :thumbup:

Added comments in blue.

Originally Posted by Mortarsprayer (Post 349720)
Hello Rob,
The VERY first step is to make sure your booster [electric coolant] pump works. I have two Sprinters and both came to me with non working pumps.

To test the pump it is a 2 minute job. The pump is on the fire wall to the left of the brake booster and down slightly. [Follow the heater hose on the EGR to the pump.] Unplug the wiring from the pump (The plug wiggles off from two pins). The pump motor is DC and polarity doesn't matter for this test. Connect a alligator clip test lead ( http://www.ebay.com/itm/10pcs-20-Dou...-/161043313433 ) to the lower pin and the negative on the battery. Connect another test lead to the upper pin and touch it briefly to the positive post on the battery. If it is silent, you need to replace the brushes or the pump before proceeding.

If the pump is bad, you can find a bunch of information on the forum about replacing brushes or ordering an alternative brush-less pumps (example: http://www.ebay.com/itm/221629371626 ).

The easiest and fastest solution is to order a replacement on Ebay http://www.ebay.com/itm/390812561799
Engine Auxiliary Water Pump Dodge Freightliner Mercedes C280 G500 0392020026

The following doe not apply for the Booster Heater OEM controls.

Once you have the pump working you can use the 7 day timer to start up before you get to your van. Also, you can reach in and push the squiggly line button on the timer to start the heater manually. From that point you can increase the number of running minutes up to 120.

If the pump is not working, pushing the squiggly line button with the engine off will run the booster heat briefly and then shut down so it does not overheat. Pushing the squiggly line with the engine running from cold start should result in the booster cycling on/off in the first few minutes and then coming back on to run solid until the coolant is past 180.

Best regards,

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