Hi all, I now have my ac and heater going, with the help of the group menbers, and again I would hate to not have accsess to the search forum, I would be lost. I have all vents opening correctly, I have replaced the following; push button control, new fan, new compressor, condenser, ac hose, acumulator, I have removed # 11 fuse from fuse box and replaced it with 30 amp fuse in a water proof housing. I have done everything suggested and still, once in a while the 30 amp fuse blows. I don"t get it. No rhyme or reason, works fine for days then it blows. When the system is working, it is great. The unit keeps the car at an even temp as it was desigened to do, I couldn't be more satisfied. If somone could give me a direction to go in, It would be great. I just am at a loss as what to do next. My car is a 83 300sd. steve

I forgot to say I also replaced monovalve and aux water pump, I'm trying to cook dinner, wash a load of clothes, take the dog out, fix my car, empty the dishwasher and straighten up the house, steve

anyone? any ideas, any help at all, can I split the fan wire from the compressor wire and have two fuses? can the new compressor be drawing to much juice? My wiring book I got from books 4cars.com shows only two things on the number11 fuse but the cover shows that the idle stabilazation is also on fuse 11, could that be drawing to much juice? what does that do ? help!!! steve

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)

thanks Jim, The compressor is 6 months old so I don"t think that is it . Your other Idea could be it. Tomorro i'll check for wire damage and thanks for the expanation of the idle stabulazation. makes sence that that to could be the problem as I watch the compressor cycle on and off with the heat on. Maybe it is drawing to much juice. thanks steve

I think #11 also feeds the backup lights. I had a bad wire off the tranny to the lights that would blow that fuse every now and then. Could not figure out why till it shorted out and started blowing the fuse everytime I backed up.

rebootit, thats really interesting as I have no back up lights, I thought it was the switch on the tranny that was bad, hummmmm thanksfor the tip. steve

that is what I thought. Even went as far as getting the part and was going to change it out when I found the burned wire. The switch looks to be a royal PIA without a lift so I ended up just capping off the wire and didn't have the problem anymore. In my case I could find nothing that would have cut or worn through the wire so it may well be the switch caused it.

were did you find the burned wire? Nere the switch? was it plain to see, or should I put it up on a lift?. thanks for your help steve

Rebootit, thanks, You got me on the right path. I checked the wire at the tranny switch, neutral safty switch I think, all was OK. Then I went to the harness up front where the ac compressor wire comes out of the harness, and low and behold, wasn't the wire pinched between the ac hose bracket and the body. All is right with the world now. thanks so much for your tip. steve

I was on a road trip so sorry for the delay. Wire I found was right by the switch, about 6" from it. Glad you found the problem.