I have a 1994 Corvette coupe. The problem is when the heat is on and the thermostat is set at max or any heat setting (car is up to tempature 195deg). I get intermitant heat out of the vents. First it will be cold then hot, cold then hot....any ideas to help me.

 

1st does your have automatic temp control. By that, I mean can you set the temp settings? If so, you might have programmer problems. Under the dash is a a/c programmer that opens and closes blend the door for your heater core to mix heated air with cold air from your evaporator. If your car does not have a programmer, the operation is controlled by the control head in the dash, which a simpler operation to replace. Before replaceing anything , to avoid any unnecessary expense, have someone with a scanner check for any body control codes first. [8D]