As it got warm this summer and I started using the A/C in my truck I've noticed that if the truck sets at idle for longer than just a minute or two, the A/C will start blowing warm air, not like heat or anything, just not cold. As long as I'm driving it blows nice and cold. It also takes longer than it should to start blowing cold air when I first start the truck and drive somewhere. I've checked the freon and it's good. Is the compressor getting weak or could it be another issue?
Check compressor gap. See what your psis are. Also, make sure there are no weeds etc in radiator and condensor area. However, its not uncommon for the a.c to blow slightly warmer at idle than at other speeds.
Thanks for the advise guys, I'd never heard of compressor air gap before so I'll check that. As far as the PSI goes, what should it be? The radiator and condenser area is probably due to be cleaned out so I'll do that also. It's not just slightly warmer, It's alot warmer like if you turned the switch to just fan and not A/C.
I began to experience the same thing when my alternator started going out. The low RPM simply could not keep the appropriate level of charge going. I would try the compressor shim first, and if that doesn't take care of the problem, then have your alternator checked.