Have a 95 c220 that has several issues that may be related. The abs light stays on and will not reset, the cruise does not function and the speedometer rests at zero. Hooked car up to scanner, and can read the mph on scanner, though speedo never budges... replaced sensor at pumpkin and both front sensors... also replaced the over-voltage relay. verified the speedo motor actually functions via cluster removal... don't know where the wire for the speedo signal drops it voltage though. Anyone seen anything similar to this before? Trying to cut troubleshooting time down as much as possible, since I already have a few hours and dollars in it. Thanks in advance...

Check for low voltage condition and also check fuses ..

Thanks, already did check for both low voltage and fuse conditions... this one has my father-in-law and I both stumped... we think it may be one of the controllers, since the speedo signal wire runs through the cruise and abs controllers both...

Speed sensor should be at cluster.. check it..

Don't know of any speed sensor in the cluster... what should I be looking for...had the cluster out and completely apart which is how I checked the motor for the speedometer was working. The tach uses another motor which is identical...the cluster is just a large circuit board with the 3 gauges attached and the clock, odometer, and temp lcd's at the bottom.... no speed sensor I could find...

I don't know Arthur, I think the C220 uses the wheel speed signal off one of the front wheels for the speedo and cruise and is part of the ABS system. I would go for fixing the ABS and you probably will fix everything.

Without looking at it with a scanner or wiring, its hard to remember how the signal gets shared. A 95 also is probably scanable on ABS

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Yes Steve, that's what we have concluded also... the speedo wire runs through the abs and cruise control controllers and on to the speedo. The speed signal, as far as we could tell, is sourced only from the pumpkin sensor. Had it hooked up to a scanner and rear wheel rotation was the only one that affected the mph readout on the scanner. I just wanted to see if anyone had ever seen this issue before and had a definitive solution. ABS was the direction we are headed at this point...thanks

SB

I think you are correct..
The E class of the same year had the cluster sensor, but I guess the C was new generstion system

I will look at the schematic to see where it comes from..

Actually this is kinda weird for a M111 car. If you look at the two drawings, X62/12 and x62/13 are two separate VSS signals. The one going from the rear end only goes to N3/4 HFM and a cruise reference resistor N4/2. Only the VSS from the other drawing (front left sensor) goes to CC/ISC controller N4/3 and A1 (inst cluster)

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__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Sir-
I have the same car, had a couple of the same problems. The speedo was just that the needle was stuck to the stop pin in the custer. Pulled the custer and cleaned the stop pin and all was well. The cruise problem was the amplifier and the resoldering all the solder spots fixed the cruise. Can't help with the ABS light. Good Luck