So far this has only happened 2 times in the past week. It will make a ticking noise upon inspection i noticed my tensioner jumping. As i watched the belt i noticed it would slip toward the front of the AC then slip back nearly aligning itself then repeat. Shut it down align the belt the ticking stops and it was good to go again. I dont know what would cause this to happen and felt i should try and nip it in the butt before i loose a belt on the road during a trip. Both times the AC has been off for both shut down and start up when this has occured.