I have a 1985 500 SEL. The AC has always worked fine, including yesterday. I went to a restraunt for lunch (I about froze from the air before lunch), and when I came out, the air was hot all the way home (about 10 miles).

The fan is cycling just fine, but the compressor is not kicking in. The fuse seems OK, but if there is a relay, I am not sure which one it is. I noticed a couple of the relays are hot after running the engine a couple a short while.

When the engine is off, I can turn the front part of the compressor clutch just fine freely. Not sure if that is good or bed. I would think it should turn if the clutch to the compressor is not on.

I had the R-12 checked, and there is plenty of pressure; it is full.

I have not driven the car in a while due to dying the carpets, and want to take the family in it for easter.

 

the relay is on the firewall if you open the hood. you will see two black boxes in there the size of cigarette box (only shorter).
pull it out and clean the contacts. use smooth sandpaper.

 

Can't find it. I do not think it is on the firewall. 85 500 SEL. Do you have a part number or picture?

 

your model is before 8/85 or after?

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03/85.

My friend is trying to tell me over the phone the same unit as you are, but his is by the transmission under the dash on the passenger side. His is also a 240 D, so quite different

 

Also, I so appreciate your help. I am sorry to seem so dumb on this matter. I have looked all over the firewall, inside the console, under the passenger and driver sides. There are several boxes on the driver's side under the dash, but they are silver. I have not been able to investigate them further, because it is so humid and hot here today. ...Dallas, TX

This is all so frustrating, because I have not driven the car for three months, due to needing front tires, and dying the carpets and interior fabric. It is a beautiful black 500 with palimino interior. It has a near perfect body, but the previous owners have been very neglectful. The right side has been wrecked, but you can only tell that from the fender weld under the hood (a minor dent). But many screws have been removed, and I am getting everything restored back from the salvage. We have a great one here; next Sunday is all you can carry out for $25! I have almost everything but new seats.

As I said earlier, the air ran fine to go get tires, but then we stopped for lunch. Before lunch, freezing! After lunch, blowing hot air.