86 300SDL: A/C continues to be a problem. Replaced the compressor/clutch, expansion valve, receiver/drier, relay, early last summer. The A/C switch assembly may be origional and I have not replaced it as it appears to operate ok. Problem appears to settle around the A/C relay (KAE) located on the fire wall, about the size of a pack of cigs. close to the MC. When removing the relay, the compressor/clutch wants to kick in and does sometimes for a few seconds then cuts out. Relay was replaced again last fall and now appears to be failing again. Removing the relay and then replacing it starts the clutch to kick in and then kick out. I acts like there is a short in the system?
I do not want to continue replacing the relay every six months. Any ideas on what would cause this? It has become very frustrating.
Thanks,
Ron

Not sure if this is related, but both the A/C Compressor Clutch and the Auxilliary Water Pump are fed from Fuse #5. If the Water Pump is seized then maybe this is causing problems with the A/C relay. I think that the ACC is fed from the same source so that may be affected as well. It might be worth disconnecting the Aux.Water Pump just to see if it makes any difference.

Good Luck

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1991 M-B 560SEL Arctic White/Grey 99,000 Miles
1987 M-B 300SDL Ivory/Palomino 229,000 Miles (sold but never forgotten)
2006 Volvo XC70 Blue/Beige
1999 Porsche Boxster Arena Red/Savanna Beige
1986 Porsche 928S Goldweiss/Brown

You may want to do a search/post on this site: http://www.aircondition.com/wwwboard/

Deals strictly with AC problems. Some people there really know their *****.

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Bill Reimels
Now down to one:
1972 300SE 3.5 W109 (Euro delivery)

Ron, Does your tach shut down at the same time as your a/c. If it does check a plug that runs on the right side of the battery and near the relay it corodes and must be fixed. You will have to remove the battery to fix. Good luck
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Pete.

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Pete.