I'm having problems with the air conditioner in my wife's car and I am looking for advice on fixing it without costing to much. I have done a search but have not found what I'm looking for.

The Problem is that it doesn't seem to be turning on

when I turn on my car's air con in my car the rev's increase and one (or both) of the thermo fans kick in and the air starts to blow cold.

when I turn on my wife's the rev's don't change, the thermo's don't kick in and the air blows hot

This started as an intermitint problem, but has now gotten to the point where it doesn't work at all. I haven't taken it to be looked at yet cause they will just say that it needs regasing, but when it used to kick in, it was really cold which makes me think it doesn't.

Now I have spent most of today changing bits from my car to hers as a trial and error way to find the problem without sucsess.

I swaped the climate control unit and any relay or fuse in the box under to bonnet that relates to the air con or thermo fans. Still her air con doesn't work and mine does.

Any suggestions?

It's not a gas issue. If there's no increase in rev's the compressor isn't engaging. Tons of posts here, quick search will sort you out.