T1N Starter Circuit Notes

Aqua Puttana

Poly - Thread Finder
I did some investigation to try and resolve some of the Sprinter Start Circuit Design. Some of what surfaced in Mackconsult's thread didn't really add up after he found that he only needed to replace his Starter Relay Transmission Relay to return proper starting. Up until he replaced the relay and restored operation it seemed that he was not getting the Starter Relay 12 volt negative signal from his ECM. If the ECM was locking out then I wouldn't expect a relay replacement to cure the problem. Edit: Replacing the Transmission Relay makes perfect sense now.

Here is that thread.
What a bugger - NO CRANK
https://sprinter-source.com/forums/showthread.php?t=32032

I needed to use the combination of the Fuel System Book and the Service Manual to figure some of this stuff out. I'm relatively confident of my findings, but do not treat it as the last word. It is what I've dug up so far.


I find these notes apply for the start circuit drawings. I'm fairly certain that my interpretation is correct.

+OBD = NAS Sprinters.
++Except OBD = Sprinters we don't get in North America

OBD = Except Built Up Export? (Vehicles built for sale in North America).
As opposed to Built-Up-Export (Vehicles built for sale in markets other than North America) Reference Drawing 8w-01-5

8W01-05TextwNote.jpg


Some Common 12V Grounds

G200 - ECM Engine Control Module negative (3 ea. wires) goes directly to ground G200. (Common/shared with Wiper/Turn signal/start control module [FB#1], SKREEM Sentry Key Remote, Horn, Steering Angle Sensor, and others.) 8w-15-07

8w-15-07GroundswNote.jpg


G202 - Fuel Pump Relay coil negative goes directly to common ground G202. (Common/shared with TCM, Transmission Relay, Heated Seats Relay, and others.) 8w-15-11

8w-15-11Grounds.jpg

Ignition Splice and Connector Notes

NOTE!!!: The FB#1 dotted box and wire with arrow pointing off show power from an Ign Sw wire or the battery. The Ign Sw wire color is in the small box on top or "BATT" if direct.

Reference Drawing 8w-10-13

8w-10-13IgnitionSwitchwNotes.jpg


Position #0 = OFF - key out, Pos #1 = ACC, Pos #2 = ON, Pos #3 = START

Multi-Function Switch has hot Ign Sw position 0, 1

Splice S255 and C201 (BK/RD) are hot Ign Sw Position 1, 2, 3 =

Splice S219 (VT) is hot only in Ign Sw Position 3 = ECM Pin # and Starter Relay contact.

C2 (FB#1 connector BK wire) is hot Ign Sw Position 2, 3 = Feeds FB#1 [Fuses #4 - Shifter Assembly, # 5 - S204, #6 - Multi-Func/Hazard, #7- S206, #18 - S200 = [ECM, Air Bag Module, Fused Ign Sw Run-Start Relay, IC Instrument Cluster]

8w-10-14 added for clarity.

8w-10-14wNotes.jpg
Cont.
 
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Aqua Puttana

Poly - Thread Finder
cont.

The 12 volt power to Starter Relay and Fuel Pump Relay drawing is interestingly found under "Charging System". 8w-20-6

ECM Pin #58 Start Relay (labeled Starter Motor Relay control)and Pin #55 Fuel Pump Relay feeds. The ECM controls the negative on both. The 2004 - 2006 VA Sprinter OM647 Diesel Fuel System reference book agrees with that. +OBD applies to our NAS aka NAFTA Sprinters or "Except Built Up Export - Vehicles built for sale in North America".

Reference Drawing #8w-20-6

8w-20-06StartFuelRelaywNotes.jpg

Note that the dotted box Engine Control Module (OBD) above the Fuel Pump Relay (OBD) has Pin #55 indicated.

As an aside. The diagram above nicely shows the Pull in (1) and Hold (2) solenoid coils. When power is supplied to the starter motor proper the voltage across coil 1 drops to zero.

227CommonPointFaultDiagnosisNote1.jpg


Splice S108 feeds +12v to Fuel Pump Relay and Starter Relay. 8w-30-18

Where does splice S108 get power? I could not track down the actual 12+ feed for splice S108, but it must may be fed from the BK wire off the Ignition Switch (hot in position 2 - 3), or maybe a relay fed by the BK wire per Dick's S1XX description of 100 series splices being direct/switched off the PDC source. (I looked closely again and still never found the origin of S108. From Mackconsult's per Doktor A's info the Starter Relay pin #86 - S108 - responds to the ignition switch position. See Dick's post #7 below.)

ECM Pin #36 +12V to the Starter Relay Contacts labeled "Ignition Switch Output (Start)" info agrees both in the drawing and in the fuel book. It is fed from the Ign Sw BK/YL wire via S219 per 8w-20-06.

8w-30-18StartFuelRelaywNotes.jpg


It appears to me that the ECM has the capability of start lockout by at least 2 one method. That is to suppress the 12 volt negative Pin #58. The other is to suppress the 12 volt positive output Pin #36 which stops +12 volt power from going to the solenoid. Oops.

Additional Edit after finding more complete information:
What was I thinking. :doh: The fairly heavy load of the starter solenoid wouldn't be fed by the ECM. It is fed by the Ignition Switch Circuit to S219 to the solenoid.

So +12V from the S219 also feeds into the ECM. That can still help to explain why a pushbutton feeding the solenoid can work. It depends upon if the ECM has locked out, or what other start circuit components may have failed.

Here's the heavy cables associated with the starter.

8w-10-11HeavyCableswNotes.jpg


FWIW. vic
 
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Fkimble

New member
VIc, I think Jim's push button solution is only good if all conditions are go for a "start" with the only problem being the delivery to the small post on the solenoid, ie either the start relay failng to pick or its output fails to make, or physical open wiring to or from start relay to solenoid. I think there is a short window time wise where the ECU is only waiting on confirmation that the engine is spinning. Very interesting thread.
 

Aqua Puttana

Poly - Thread Finder
Some misc. information


So I got a call from Dr. A (Thank you sir, you are the best).

Attached is a picture of the relay seat for the starting system under the driver seat. 87 should have 12 volts when performing the start operation (check). 86 should have 12 volts when ignition is on (check). 85 should have continuity with ground (no check). And 30 if 12 volts is applied should kick the starter over (did not check at this point because of no check on ground).

So the non-continuity with ground has me really concerned. I even put my jumper cables on neg terminal of the battery and checked continuity with 85 and nothing comes up.

My chassis ground cable seems to be intact. But all I did was grab and and try to move it around.
RelayPins.jpg

This shows the location of my 2004 Starter Relay.

023a2004FuseBlock2PicNotes.jpg

2004 RelayswNotes.jpg

Starter Relay Part Numbers
Starter Relay 2001 - 2007 Dodge Sprinter (verify application before ordering)
#5101505AB

Some other possible part numbers
(verify application before ordering)
05101505AB ; 05101505AA; 05103830AA; 05129614AA; 05129616AA; 05138902AA

More possibilites are here.

https://sprinter-source.com/forums/showthread.php?p=238896#post238896

Doktor A recommends sticking with Bosch starters. There is some history of off brand aftermarket starters being dimensionally out of spec which can damage the flywheel/ring gear. Valeo is also an OEM supplier.

Bosch Starter part # 05134510AB
Valeo Starter part # 05117537AB

A current listing which specifies Bosch.

http://www.amazon.com/Bosch-SR0473N-New-Starter/dp/compatibility-chart/B000EPR0DG

From some of the words in the description it may be a rebuild?

vic
 

autostaretx

Erratic Member
Vic wondered:
Where does splice S108 get power? I could not track down the actual 12+ feed for splice S108, but it must be fed from the BK wire off the Ignition Switch (hot in position 2 - 3), or maybe a relay fed by the BK wire.
I believe the "1" in "108" means that its only upstream fuse is on the Power Distribution Block.

(it can go through relay contacts and switch closures enroute, but the only fuse is on the PDB)

--dick
 
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Aqua Puttana

Poly - Thread Finder
Vic wondered:

I believe the "1" in "108" means that its only upstream fuse is on the Power Distribution Block.

(it can go through relay contacts and switch closures enroute, but the only fuse is on the PDB)

--dick
Dick,
Good input.

All the Power Distribution Blocks are quite large amperage. Given the wire size and how conservative MB is with fusing, that seems unlikely to me, BUT... I don't know so I can't really confirm or deny it. The convention you mention does seem to hold in the diagrams I looked over.

Somebody smarter than me will need to figure this one out. I've done about all I'm going to do so far. I am considering adding a little step-by-step basic test procedure here if I'm so inclined.

Thanks for the reply.
vic
 

autostaretx

Erratic Member
Vic, i think i agree with your suspicion that S108 is tied to the 14-gauge black wire coming from the ignition switch's Run/Start contacts.
Those contacts are fed from a bus bar behind Fuse Block 1, which is fed from S101, which is fed by Fuse 6 (100 amps) in the PDB.

Even though 8w-10-13 says "from Fuse 21", looking at 8w-10-12 shows that it's from the top of fuse 21, not fused by fuse 21.
(fuse 21 handles the cabin blower fan via the notorious resistor block).

...probably...
--dick
 

Aqua Puttana

Poly - Thread Finder
Vic, i think i agree with your suspicion that S108 is tied to the 14-gauge black wire coming from the ignition switch's Run/Start contacts.
Those contacts are fed from a bus bar behind Fuse Block 1, which is fed from S101, which is fed by Fuse 6 (100 amps) in the PDB.

Even though 8w-10-13 says "from Fuse 21", looking at 8w-10-12 shows that it's from the top of fuse 21, not fused by fuse 21.
(fuse 21 handles the cabin blower fan via the notorious resistor block).

...probably...
--dick
Dick,
Certainly the black wire for S108 would be consistent with the black wire off the ignition switch. I think you've nailed it.

See. I said someone smarter than I am. :thumbup:

Thanks for taking the time to chase it down.
vic
 

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