Ok I have your attention. I am posting this here because “gears heads” are where the smart people hang out. I have a 1989 Corvette and the blower motor only works on high. Ok, I have seen this before. I changed the blower motor and it fixed the problem. Not this time, I changed the blower motor and had the same results. Any ideas on what to check next?? It hard to run the AC on high or off, either you are to cold or to hot.. Thanks guys.