Wiring Heater Booster to run from Switch

a bottle of gray goose for info on this mod for a 2008 freightliner.

mlf570 said:

a bottle of gray goose for info on this mod for a 2008 freightliner.

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Info for the full on operation of all fan speeds and the heater, or information for the more simple engine pre-heat for cold ambient temperatures?

For the pre-heat, here's your information.

Residual Heat Mode (aka T1N REST) exists per the 2008 NCV3 operator manual.
Page 222
http://aie-services-2.net/Sprinter/2008-Sprinter-OwnersManual.pdf

***************************
Residual heat mode

The engine stores residual heat after
long periods of driving. You can use the
residual heat of the engine to heat the
stationary vehicle for a further 30 minutes.

The heating period depends on:
 * the coolant temperature
 * the interior temperature selected
 the on-board voltage

The blower runs at speed 1 regardless
of the position of the airflow
control.

To switch on: turn key to position 0
in the ignition lock ( page 111) or
remove it (the key that is, not the ignition switch ).


Set as required:
 temperature ( page 220)
 air distribution ( page 221)
 the air vents ( page 215)

Press the°switch
( page 218).
The indicator lamp in the switch
comes on.

To switch off: press ° switch
again ( page 218).
The indicator lamp in the switch goes
out.
Residual heat switches off automatically:
 after about 30 minutes
 when you switch on the ignition
 if the battery’s voltage drops
***************************

My approach would be to work exclusively with the 12 volt power wire supplied to the Aux Electric Coolant Pump during the Residual Heat operation. That power will provide 30 minutes of pre-heat operation of the Espar heater without much fancy modification or relay/switch logic.

My same basic diagram for the T1N Booster Heater will work for the 2008. Wire colors may have (likely have?) changed so the Espar wire colors and the wire for the electric coolant pump power will need to be located/verified. The Espar connector pin numbers should be consistent.



More T1N info for the DPDT switch modicication is here.
REST/Booster Engine Pre-heat with DPDT Switch Modification
https://sprinter-source.com/forums/showthread.php?t=36797

What size bottle? You said "info", not a complete detailed solution.

If anyone applies the DPDT switch to the NCV3 model it would be nice if some of the wire color details, access, etc. were posted as a Write-up in the NCV3 section.

vic

1reddog48 said:

FIXED!!!
Thanks Chris. Even though I had checked my wiring twice, I guess my eyes were open, but my mind was not. I had it wired as the original post indicated, not the corrected one, Even though I thought I had gone by the corrected diagram. Re-visited relay #4 and found the problem. Now it works like a champ van on or off!
Just as an aside, when I got home from being gone for 2 weeks to check this out, the battery had been drained significantly. I suspect that the way I had it wired, INCORRECTLY, was backfeeding something and drained that battery. I am not positive about this, but this is what I suspect.
Does anyone know if the heater booster OE function is supposed to stay activated after start, stop engine, re-start cycles? If I start the van, activate the heater booster (little red light goes "on") and shut the van down with the red light still one, it WAS lit again when I started the van the next time. I have not checked this since I have corrected the wiring mistake I made, just wondered if anyone knew for sure if this was how it was supposed to function.
This is a GREAT mod for those of us living in chilly areas, thanks to all who have participated in this thread.

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What was the fix? Which wires were incorrect on the 4th relay?
Did you use 3 SPSTs and the 4 th relay a SPDT?
I have 4 SPDTs and I am getting an ABS and an ASR light with the engine on. Will your fix fix my problem?
My unit fires up and works perfectly except for the dummy lights which sounds like I am backing feed 12 v while the engine is on.
I am wire per the original drawing on the first post here.
Thanks, Rex
'06 VH

The original post has an error in the diagram. Find the post by Lepapehermann in this thread that corrects it. If you are familiar with relays, you can see that the purpose of the 4th relay is simply to "put" everything back to normal when the system is not on. With the system on, you then use the relay set to power things up. It is fine to use SPDTs for the first 3 relays, you simply don't use their full capacity. You must use the SPDT for the last relay because in effect, with the relay off, there is a connection through the relay that restores the original wiring condition.

I hope that I am making sense here. I have had this mod in place for over 5 years now and it works great. I have the 7 day timer. Earlier this year I need to replace the exhaust on the ESPAR, but other than that and the pesky elec. water pump, no issues at all.

Chris

Here's the correct diagram you want - https://sprinter-source.com/forums/attachment.php?attachmentid=19024&d=1259341385

Also, a real cool modification I did in a couple hours with the 7 day timer (although the switch in the above diagram could be the remote (relay) instead of the 7 day timer)) can be found here - $70 or less Car Alarm Remote start for Espar 7 Day Timer Upgrade If you were to use the remote as the switch you would want to put 12v instead of my negative pulse solution to pin #5 on the 7 day timer.

Chris, some would have a problem with this given my high level 'overview'. Sounds like you would have no problem. Works awesome and 1/10th the cost of doing it compared to buying the remote through Espar..

I thought about using a remote to turn on the ESPAR, but our primary usage is warming the van up in the morning in the driveway. So, either I turn it on for my wife or she sends one of the kids out to turn it on. 15-20 minutes later and all good. My wife uses the rest function a lot, or just hits the ESPAR again sometimes when she is in somewhere. I think we would have a tough time in MN without this mod.

Chris

cahaak said:

I thought about using a remote to turn on the ESPAR, but our primary usage is warming the van up in the morning in the driveway. So, either I turn it on for my wife or she sends one of the kids out to turn it on. 15-20 minutes later and all good. My wife uses the rest function a lot, or just hits the ESPAR again sometimes when she is in somewhere. I think we would have a tough time in MN without this mod.

Chris

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I guess having a couple kids to run out in freezing temps is as good as a remote to turn it on!!

The remote mod is super easy. I can't believe anyone would pay $1000 to Espar plus install time or $$ when you can do it yourself for a fraction the cost.

Thank you Chris and Vanski for the reply! I will change the lead from leg 87 to 30 on the 4th relay. That should fix my problem.
Yes I like the remote mod and will probably have to do it. I like all mods I am addicted.

Question: Has anyone found a way to command the heater, through the harness, to stay in low heat mode, rather than cycle between low and high heat to maintain water temperature? Such as through one of the "unused" pins, or talking to the heater through the diagnostic line?

I do not want to mess with the heater booster's internals since it may interfere with the system that shuts off fuel on flameout.

seans said:

Question: Has anyone found a way to command the heater, through the harness, to stay in low heat mode, rather than cycle between low and high heat to maintain water temperature? Such as through one of the "unused" pins, or talking to the heater through the diagnostic line?

I do not want to mess with the heater booster's internals since it may interfere with the system that shuts off fuel on flameout.

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To the best of my knowledge there is no low burner output enable, or high output disable brought out to the external connector plug.

The Espar D5 wiring is here (along with other schematics).

https://sprinter-source.com/forums/showthread.php?t=30191

That said, the low output only capability may be available through some of the Espar control packages available.

vic

Today, I got all the power moved to the Aux battery for the Espar. I used Tapa Circuits to push power in to the fuse box. This way I can always just pull the add on and replace the fuse for factory installation.

To use these, I don't put a fuse in the lower position, where the 3 amp fuse is in the picture.
I only put a fuse in the top position, where the 10 amp is. This by feeding power in to the pigtail, the outermost tab is powered and fused. Plugging this in to the fuse box the correct way will power the circuit and be fused.
Under the seat (fuse box 2) there are two points that are fed power. One feeds 25 amps and is likely the main power for the heater. Previous posts talk about these connections and they are different numbers for every van, so I won't discuss them further.
But to use the Tapa Circuit on this fuse box, I had to push the fuse box back from the access door about a half inch. I got two longer mounting screws and some plastic spacers at Ace hardware.
I had lots of trouble trying to find the power for the REST fan, eventually giving up. I found the fuse that runs the aux water pump, Block 1 fuse 20 labeled Heater Control. Amazingly this same fuse runs the REST fan. Tested things out and this fuse does not control the heater for other fan functions. So it only took the one line there to get Aux power.
While I was there, I also powered the fuse 8, interior lights. This does the radio power, cigarette lighter and lights.
The other power plug on the dash is powered by a fuse under the seat and I used the same process to power that.
I replaced the momentary button for the jumper mode of the isolation relay to a switch. That way, with the switch on, the van battery would feed these circuits even with the aux batteries shut out of the system.

ECU said:

Today, I got all the power moved to the Aux battery for the Espar.

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Awesome! What kind of current does the system consume while starting / in high output mode
/ in low output mode (which will help size a house battery for this?)

seans said:

Awesome! What kind of current does the system consume while starting / in high output mode
/ in low output mode (which will help size a house battery for this?)

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I have the factory installed espar, no hi/low output mode. I have two optima blue agm (75ah?).
My install was a switch powered by the REST button sending to the Espar, tapping in to the line that already goes from the heat control to the Espar. The other trigger wire was converted from 'power via ignition' to 'full time power' by Tapa jumper thing to fuse block #2.
So in this mode, as REST goes off at start, so does the Espar.
I don't know the amp draw. The isolation relay doesn't connect until after start, so it shouldn't be an issue.

The factory espar is at high mode until 180 degrees is met. Then it drops down to low mode.

Just over a year with this mod done and 100% happy. So awesome to start the heater and have a warm engine and cabin heater instantly. Not to mention no issues with starting the diesel when in the back country away from any electrical plugs (after a day of splitboarding, etc)

Also, wicked for camp showers and hot pressure washing through my auxiliary set-up. Still not finished, but have a tank to build when I have time (new year) and have a few new additions. Ie, coolant heated rear fan and addition of a low voltage disconnect since I'm only running the stock battery. I would also really like to include for a bluetooth switch so I can turn heater on from my house or wherever I might be.

Either way, thanks for the work on this one guys. Works very well!

As far as current? I ran a 10g wire from the Aux batt with a 30a fuse. All the taps split off this. Each tap uses the original size fuse for it's line.
The total amperage adds up to more, but I'll wait to see if the 30a fuse blows and see what happens there. So far, I turned on all lights, ran the Espar and fan and the radio all at once and the fuse didn't blow.

Shibby! said:

Also, wicked for camp showers and hot pressure washing through my auxiliary set-up. Still not finished, but have a tank to build when I have time (new year) and have a few new additions. Ie, coolant heated rear fan and addition of a low voltage disconnect since I'm only running the stock battery. I would also really like to include for a bluetooth switch so I can turn heater on from my house or wherever I might be.

Click to expand...

I'd love to see your write-up when it is done. I would also like to run the coolant through a heat exhanger to get hot water. But I think I like the idea of a rear fan best. Even though it is feet away, the intake for the dash air is close enough to the heater booster exhaust that I get a diesel smell in the van. It would be great to grab fresh air far away from the heater booster exhaust.

Finally got some running time on the Espar and the switch modification. My aux batteries were run down. At one point the REST stopped due to the battery level being too low. Another day, it wouldn't run due to the fuel level being too low. So it is good to know that these features still work with my modification. Plus, I was able to verify that the circuits are being run off the aux system and starting is no issue!
Also got about a 40 minute wait in the vehicle in cold weather and ran the system a couple of times. The Espar does drop to a low speed every once in a while.

ECU: How is this setup working in the long run? I want to make sure I understand the install. In order to run the Factory Espar on demand from aux power all I would need to do is run power via a tapa-circuit to the above mentioned fuse holders (block 1 and 2). I am thinking I would run a single line to both like you, but add a switch so that when I wanted heat I just flip the switch, I don't mind turning it on and off manually. Does that sound like it would work?

If this would work, it seems like a much more straight forward and simple install than the others I have seen out there.

Thanks!

It has fired up again this year. To operate, I have to turn on REST and a dash switch. The REST controls the heater fan (low) and the circulation pump. Some of the other mods turn on the heater to have full fan control and you have the power the circulation pump too.
My mod was to pull power from the line going from the heat control to the water pump that is active when you turn on REST. I sent this to the Espar via the line from the heater that normally tells the Espar to run (with a switch in to control and a diode to prevent backwards feeds)
The Espar has several +12v feeds. Only one provides power to run and that comes through a fuse under the seat that I jumped to be powered all the time rather than by ignition. The other +12v line from the heater is just a signal to operate. Another is output to the fuel pump.

I'm at a point where I could test low starter battery conditions. My starter battery has been sluggish and I checked yesterday. 11.4v after resting all night with no load. So with my wire setup, will the Espar fire? Or will the system logic say that the starter battery is low and stop? Since the ECU is on the starter battery, I'm thinking that it will not run. I have the Espar wired to my aux batteries.

Hey ECU.. Man, I bet this took 1/16th the time of my modification.

Is it limited to the 30 minutes the REST will run?

Regarding the low voltage, I thought the heater was wired to your house battery? Or are you stating you are concerned because the fan, the coolant pump, etc are still wired off the starter and only the heater (the lowest consumer once it's running) is wired off the house?