A/C not Working

My A/C is not working on my 1994 Metro 1.0L. Any idea where to start. My fan works, the light on the A/C switch is on, refrigerant ( R134a ) is full. How do I test the Compresser, or relays? I noticed the black wire off the compresser has a bad conection. Does anyone know what this wire does?

Check whether the condensor fan is running. If the A/C is the same as what I have there will be a separate fan for the condensor (as opposed to the fan for engine cooling). Also see if you can get a hold of a manifold gauge set and measure the high side and low side pressures. If they are approximately the same the compressor is not running. Also listen and see if you can hear the compressor - it has a distinct sound (bit like a refrigerator). And yes, there should be wiring from the switch to the compressor - this engages the compressor clutch. If this is not connected properly the compressor will not run.

If the compressor is running then maybe it is low on refrigerent - you can also get a hold of a small thermometer and measure the discharge temp and ambient temp and then use a P-T chart to see if the charge is low.

When should the fan kick on? I will hook up the black wire to the compresser and see if if it kicks on.

The condensor fan should come on when the A/C is on regardless of whether the compressor is working or not. If that does not come on there may be a problem with the A/C switch wiring.

Thats not good, because the fan is not working. I guess I need to look at the wiring diagram of the whole A/C system and start from the begining. You ( or anyone ) wouldnt have the wiring diagram they could post?

Yes, I do have the wiring diagram but it is for a 2000 - I'm not sure how closely it matches your model year. maybe someone may have the diagram for a 94. Easy thing to check is the fuse - if that is blown then the compressor clutch as well as the fan will not work.

Does anyone know of a way to test the A/C compresser in, or out of the car?

You can test whether it has seized up by removing the pulley and clutch coil and rotating the compressor manually. If it will not turn it may have sized. Apart from that I do not think it is possible to diagnose damage internally as it is a sealed unit - normally this is done by using a process of elimination by using P/T charts and a manifold gauge set to isolate the likely cause.