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.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".