W126 1985 280SE(Europe) A/C Compressor not working

Feb 27, 2005 7 Replies

Hello.



I need help to trouble shoot compressor not working after switching on the A/Cond. If anybody can provide the wirings control it and are they relay switches or sensors which could be faulty? Someone told me the common fault is ignition key giving poor contacts, I have changed a new switch attached to the ignition key but problem not fixed.



Thanks in advance. Marks


If the system is too low on refrigerant the clutch won't engage, check your level.

Compressor could be not working due to insufficient Freon charge. I believe there's a switch that detects this and so protects the compressor from being damaged.

Have an A/C shop check the system's Freon charge before messing about with its mechanical parts.

Always check the basic things first.

Freon 12 at full and pressure switch is in good condition. My A/C is a twin temperature dialers control type.

Freon 12 at full and pressure switch is in good condition. My A/C is a twin temperature dialers control type.

Dunno about your particular car model, but in my car (86 190e) The deal breaker with the AC was a loose serpentine belt... Not loose enough to make noise though.

Replacing the tensioner and the belt, magically also fixed the AC.

I would first check to see if the magnetic clutch works. Simply run a jumper wire from the connector on the compressor to the positive side of the battery. You should hear a "click" as the clutch engages. If you have two leads on the connector going to the compressor you need to ground one of them. You might also use a test light to see if you're even getting current to the compressor. Good Luck!

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