stevelewis,

I am not too familiar with the problem you are having, nor am I really sure of how the idle stabilization gizmo works on a Diesel, so this is a guess. I am hoping it will inspire someone to correct me.

On a gas car, when the engine is cold it gets a richer mixture so it will idle correctly. This gets to be a bigger chore when the a/c is on. The a/c load is intermittent and if there was not some means to increase the idle speed, when the a/c cycled on the engine speed would drop. So there is a means to handle the idle speed when the car is warm or cold and with or without the a/c running. The gizmo that does all this is, I believe, the idle speed stabilizer.

The a/c cycles on an off with a clutch, which is about all the compressor current draw is used for, as the engine drives the compressor itself through the pulley. If the clutch is going bad, it is feasible it could be drawing too much current.

It is more likely the wire has a worn spot and is intermittently shorting to the frame or the engine. After twenty years of being shaken by the engine vibrations, it is not uncommon for chafing of the insulation to give these kinds of results.

I hope this helps, and inspires one of the other members with more direct experience with the idle stabilizer and the rest of the a/c system to pipe up. Good luck, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)