I have had my truck in recently to have the A/C checked. They told me it was 1/2 lb down on freon. They charged the system and put a dye stick in. I have been driving it for a month with no problems...........until yesterday. I turned on the A/C in the afternoon and it blew air WARMER than the outside temp (it was cooler to roll down the windows!). It was only about 80 outside but the A/C didn't cool at all! I have not gone back in to have them check for a leak. BTW, do they just shine a black light on the engine compartment and the dye will "glow"?

Any way a couple of hours later I got in and it blew COLD! Why would it work, then not work, then work again? :confused:

Depends on what dye they used some you can see with your naked eye the other you need the special light. Auto zone sells alot of different type of those kits.
second you need to check what the presure is at if it is to high you compressor won't work right and the air isn't aways cold. I've had my truck for over a year and a couple months ago I was getting the same problem cold then not cold so I check the pressure and it was way high some how (110+ psi) I dropped it down to 40 psi. and it's as cold as ever now I hope this helps.

I got a recharge kit from the auto parts store. Is this something I can do or is it a more precise process which would require better equipment that what I have?

first thing you should ck is to see if the AC compressor is running if not you may have a faulty pressure cycling switch

My truck was doing the same thing and the dealer replaced the pressure cycling switch and the filters inside the cab. The a/c works all the time now.

Thanks guys. This was the first time it has happened to me. Since Friday it has worked fine.

Were you still able to turn the fan off or down? I had a problem where it would short out and go to full defrost and the only way to get it to go back to cool or even be able to shut it off the fan was to turn the truck off.

Fan still worked but the AC did not.

Alright, the truck i had the fan still ran but you could not control it up-down or off.