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

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

73
Hank WD5JFR
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Freon 12 at full and pressure switch is in good condition. My A/C is a twin temperature dialers control type.

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

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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.
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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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