OER Reproduction heater motor resistor for various GM air conditioned models. Each resistor is an exact reproduction of the original GM component, designed to fit and function just like the original AC Delco resistor. The blower motor resistor is responsible for controlling the speed of the fan. This resistor mounts in the heater box in the engine compartment of the vehicle. Because the speed of the fan is a setting that is frequently adjusted by the driver of the vehicle, these resistors are often under continuous stress or strain which can cause the resistor to eventually fail. A common symptom of a bad resistor is a blower motor that is stuck on one speed or a blower motor that does not work on certain settings. Another symptom of a bad resistor is no power at all to the blower motor resulting in no air from the vehicle's vents. Applications: 1964-72 Chevy/GM Pickup with factory AC 1967 Camaro with factory AC 1965-67 Chevelle with factory AC 1965-68 Impala/Full Size with factory AC 1968 Chevy II/Nova with factory AC 1968 Corvette with factory AC 1968 Firebird with factory AC