94's gostly A/C

My 94 camry's air conditioning has a mind of it's own. Sometimes it works great, other times it blows hot air. For instance, I just turned it on from a cold start and it blew cold air 40 deg below ambient for 15 minutes. I turned the A/C and the car off and let it sit 5 minutes. I cranked it back up and went for a drive. Within five minutes it was blowing hot air. I shook wires, swapped a relay, still no cold air. Any suggestions?

Might be your A/C relay is heat sensitive and needs to be replaced.