J spaulding

I am looking at a 1996 129 but I am seeing that it is having the dreaded wire problems. The gas gauge and temp gauge shake a little bit on occassion on their own. Has anybody ever replaced just the specific wires for these gauges or does the total wiring harness have to be changed for sure in order to keep the problem from spreading?

MB-Dude

I'd suspect more a connector problem than a specific wire issue. Or perhaps something within the cluster; a poorly seated circuit board, etc. I'd try reseating the 2 connectors in the back of the cluster. And while the cluster is out, try reseating the board connectors within.
Cheers,
Jeff

J spaulding

Thank you for the information. If this is true then it would make a huge difference in this car as far as me buying it. Isn't it true, though, that the SL600's go through a wiring harness change to solve this problem? I have heard that the biodegradable wiring does fail like this, especially in the lengthened 600 motor.

MB-Dude

It is true that Mercedes, in general, had a severe wiring insulation issue when they used biodegradable materials. But that issue was resolved during the '95 model year. My '96 SL600 has the original harnesses and I have had zero problems traced to electrical wiring. Oh, a loose connection now and then. But no insulation issues. And I just inspected them recently due to a failed starter issue. That said, the engine compartment of an R129, V12 gets quite hot. So do diligence relative to wiring condition under the hood, even though it's not biodegradable insulation. It just gets brittle from engine heat. But the rest of the car, I wouldn't worry too much about it. And the problem you describe would not be associated with the engine harness, anyway. IMHO
Cheers,
Jeff