[LBJ]

68gold/white, Based on what I have had happen on my previous 91 GMC, clicking means your actuator is stripped out. With my 2004 Chevy, no noises, just a blast of hot air all the sudden on the driver's side. On my 77 Chevy, some of the doors are controlled with vacuum lines. Those had broken down and had to be replaced - heck to get to. There is also a "HOT/COLD" mechanical lever that controls overall temp that can be adjusted under the dash to make it shut completely, as required.