The OVP relay is one of the
very common problem areas with our cars along with wiring harness, throttle actuator, climate control unit, AC evaporator, etc etc.....
The original OVP design was flawed and the unit was replaced with a new unit with a different part number.
original OVP (defective): 000 520
52 45
new OVP: 000 520
67 45
The number is stamped right on the side of the relay, most likely in the back where you can't see it unless it is removed
A bad OVP can cause ALL kinds of driveability issues. Search it and you'll be reading for quite a while.
Phil has OVP's here at fastlane for $72-ish.
There were three different harness part numbers for the W124 M104 engine 1993-1995 model years. They were
ALL made with degradeable wires, they just had subtle differences in connectivities to peripheral stuff.
I don't think Mercedes put out an "updated" (new) part number on the new harnesses......that would be actually admitting that they did something wrong when they originally made them out of biodegradeable wires....and we know that won't happen! I think the part number remains the same as the original, and the
only way to tell whether it's made of non-decomposing wires is to check the born-on-date on the tag (or look for decomposition!). When I replaced my harness, I ordered and received the same part # as the original.
They put bad harnesses on cars starting in 1993 and lasting all the way through the rest of W124 production, if I'm not mistaken. My car was manufactured in April of 1995 and had a bad harness. So, since your car is a 1994 model, then its original harness was made from degradeable wire.
BUT the tag you have seems to have TWO dates on it. I don't remember mine having 2 dates; I'll have to take a look. One of the dates is 2001, so my guess is it's been replaced. but what's the deal with the 1993 date?
Brian