Since my throttle actuator went bad, I have researched and followed most threads that have questions with these units.

I have found that there are two reasons why these units go bad:

1. there are potentiometers that wear out.

2. the wiring harnesses, especially on 1992-1993 models, go bad. The insulation that Mercedes used was sub-standard, and flakes off, causing the wires to short out.

I was under the impression that neither of these can be replaced separately.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

In my case, the 1992 300E, it is apparently the safety switch that is bad. It sometimes, not always, stays open when it should close, which means it incorrectly shuts off the fuel pumps and causes engine to stall. It is temperature related, only happens when engine is cold and warming up, not when it is at full operating temperature.
And I am told it will be something in the order of $1500 (part and labor) to fix, all for a switch that probably would cost $10 or so if sold separately. Aggravating!

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DavidB29
1992 300E with ASR
35 years of Diesels until now!