Hi there, 

the air conditioning system in my 2005 Ford Focus doesn't seem to be working (I get no cold air). I can't hear the compressor kick in when the button is pressed and their is no "click" from the relay. I checked the relay by swapping it with the horn's. The horn still worked after the swap so I don't think the relay is the problem. Can anybody advise me on what to try next? I'm reluctant to have the system recharged or gassed until I can verify that the compressor still works. 

Thanks. 

The system won't engage the compressor clutch if the gas level is low.

Only option is a leak test and re-gas.

Sent from my SM-G930F

8 hours ago, Alex.t said:

verify that the compressor still works

For diagnostic purposes, it is possible to bridge the a/c relay. Remove the relay, and identify the coil contacts. Then bridge various combinations of the other 3 used contacts in the socket, to see if the a/c clutch solenoid pulls in, and the compressor starts. (Do not bridge the coil contacts, it could damage the pcm).

Do not run it like this for longer than needed, it may damage the compressor if there is not enough gas or oil.

Depending on variant, there are either two pressure switches in the a/c circuit, or one switch and a sensor. These have to be correct for the system to work.

If the pressure has only just dropped below the operating point, and has not been topped up for several years, it would be acceptable to top it up now. If the pressure is very low, or it has been re-gassed in the last two years, then it needs the leak fixing first.

If you do get it working, use it at least once a week, all weathers, just for a minute or two to give it a stir. This keeps oil in the compressor, protects the shaft seal and all the moving parts.