stock 2001 XJ. The A/C will work just fine upon intial start up. After a while(usually at normal op temp) I will get just hot air. This will last from 30 sec to until I shut it off sometimes. After it sits,I can start it back up and the cool air is right there.ONce I drove about 20 miles to eat. The first 7 miles I had nice cold air. then for about 7 miles -hot air-then the last7 back to nice cold air. My A/C mechanic had it for two days and could not find anything out of the ordinary. SUGGESTIONS?

 

I have a similar problem. Ive checked a few things and im thinking its some kind of electrical short. Im not quite sure how to check and or fix it. Im thinking about getting a new compressor but im not positive that will fix it

 

Swap in another relay from the box to eliminate that as a problem. Sometimes the compressor clutch needs to be re-shimmed.

If your problem is intermittent, I'm inclined to think that this might be the issue.

 

on further investigating found clutch to be bad. Replacing compressor with new one from autoaironline.com(best deal I could find)