Vectra Air Con Compressor

The clutch on the compressor is engaged by energising an electromagnet which forms part of the clutch. This clamps the driven plate to the pulley and forms the positive drive to the compressor shaft.

Are you sure that there is enough refrigerant in the system? Low system pressure is a much more common reason for the compressor to not cut in. There are pressure switches in the supply line to the compressor coil. It is possible to test the coil by measuring its resistance (approx 10 ohms or less), or by connecting a 12V supply to its input terminals. Ensure that the supply is connected the correct way round, as there is often a surge protecting diode in the coil, and if the supply is connected incorrectly it will cause a short circuit. The clutch assembly is able to replaced seperately from the compressor, although special tools are required to do so.

HTH

Anthony Remove eight from email to reply.

First check for 12v appearing at the compressor clutch wire when the a/c button is pressed and engine running.

If not then check for continuity across the low pressure switch ( if not- then you've lost the gas) if there is, check compressor earth and a/c fuses / relays etc.

If there is power, then the clutch has failed (quite common on some makes of compressor fitted to Vectra's and Astra G's). They can be removed and replaced on the vehicle, but its a far from easy task and you need several special tools to hold the compressor shaft stationary whilst the clutch is removed. Best left to a dealer or a/c specialist. A recon compressor (+ system service & re gas) may be more cost effective.

Tim..

Hiya Mac, I had a Astra Mk4 where the Compressor wasn't working, I went down to a numbe of Air Con specialists and was always recommended to change the compressor than to try and repair it. However since this is a common problem I know that Vauxhall are provideing reconditioned ones and taking the old ones in as Part Exchange so maybe this will be worth looking into. The vauxhall dealer that gave me a price on the recon was Monorep in Norwood Green, Southall. I never ended up repairing the Air Con system as the car was a insurance write off shortly after me investigating into it.

Hope this Helps

Ritz

There are safety interlocks to prevent the clutch engaging if the refrigerant level is low etc. This is by far the most likely cause. However, you could check that there is 12 volts at the clutch (check between both wires if two) with the AC switched on.

Thanks Guys.

I didn't realise the system had a low refrigerant pressure switch - although thinking about it now it's pretty obvious!! Anyway I guess I better look at this first. Where is the dam thing? Senp an enjoyable hour following pipes around the engin bay as best I could but can see any electrical connections to the system other than the compressor clutch.

Incidently there is now power to one side of the compressor clutch connection (other side is a good earth) which seems to confirm what you guys suggest - it's not the compressor.

Thanks again for your input.

If I could type the above would say NO power to compressor clutch, not "now power".......Sorry!!