A/C problem in 99 Jeep Cherokee.....

I have been having a problem with my air conditioner for a while now. It starts up and blows cold for about 7 miles then it changes to warm, kinda humid air, and stays that way. It takes about an hour of the jeep being turned off before it blows cold again. I hooked up gauges, and everything was fine, it was fully charged and pressure was what it should be. Any help would be appreciated, it is hard to drive without the a/c when it is 105 outside! Thanks!

Are you sure your cold air is not going into the engine bay? My A/C lines get frozen solid after 10 minutes, even in this un-godly Florida heat. IF you've got the proper coolant and coolant level, check the circulation fan connections on the passenger side firewall. Stick your head inside the engine bay and feel around the fan housing for cold air. Also check your A/C controls. It might be a simple vacuum connection or a loose electrical connection.

Otherwise I'd say the A/C controls are shot internally ( the little rheostat do-dad that controls the temp level is'nt making contact on the cold side and defaults to the fresh air intake)