I own a 1994 C280. I had never had any stalling problems until my car shut off on me one day while I was driving. Once I had taken it in to my local mercedes service shop, they told me that the wiring harness was almost completely destroyed.

Once the harness was replaced by a dealer, the dealer told me that now the car won't stay running and that the HFM control unit must now be replaced for about $2000 dollars. I am curious to know if a short-circuiting harness could have fried the computer.

Any insight into the matter is appreciated.

[This message has been edited by blakebab (edited 01-18-2000).]

[This message has been edited by blakebab (edited 01-18-2000).]

This is possible, however I do not know how probable. I have never replaced one on a car. I guess the dealership needs to tell you why. I believe you are on the right track though. If your car is out of warranty, I think you will have to demand to speak with the factory rep to have the computer done under a "good will service". I hope all goes well, but you won't get anywhere without the factory guy there and being nice.
Thanks for the question

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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

The answer is yes. This has been an on going problem w/cars in this era. We posted warnings on this type of engine wiring harness almost a year ago. See tech tips. What is the mileage on your car?? Many times Mercedes has picked-up the tab on this repair if the mileage isn't too high!!

Hi, blakebab:

Go to "The Pro's Tech Tips" and search the topic "Check your wiring harness". Are those the wire harness you are talking about? For '94 C280, they are two wires connected to the thermostat housing. Good luck to you and keep us (at least me) updated about the repair.

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Harry (94 C280)

The dealer replaced the defective wiring harness, transmission harness, and another harness that was defective, and paid for all under a goodwill service(which I was extrememly happy about). What I was upset about was the HFM Control Unit had to be replaced.

The dealer told me that the car would not stay running (stalling, etc. - a problem I have never had in the car)after the wiring harnesses were replaced and the control unit must be replaced. The dealer and the Mercedes Zone Rep. stressed to me that a faulty harness could not have damaged the control unit(when several independent reps have told me it could). The Zone rep did offer to help me out as much as he could (the matter is not resolved yet) and I do not have my car back.

I wish I had known about this defect before I had taken my car in to get it serviced originally. This has been a long ongoing problem and my car had been mis-diagnosed by several independent servicers. I am 23 years old and straight out of college, and this is the first car I bought out on my own. Needless to say, this has been one headache after another, and I don't know if I will ever buy one of these things again.