For no reason my AC blows heat. Sometimes as soon as I start it and sometimes just driving down the road after it's been working fine. I'm not talking the AC goes off I'm talking the heater comes on. Shut the truck off, not just the AC,for awhile and it's fine again. Any ideas?

'04 Z-71 5.3L

 

Maybe you should check your AC pressure switch. I had one malfunction on my Jeep and it did something very similar. I don't think the heat is actually coming on, but its blowing hot air from the engine compartment into the truck. Check the switch (usually located on the compressor or near by) and refill your AC coolant. Good luck!

 

what year is it?..doies it blow hot out 1 side or both?