OER reproduction heater blower motor resistor for various GM non-air conditioned models. Each resistor is an exact reproduction of the original GM component designed to fit and function same as the original AC Delco resistor. The blower motor resistor is responsible for controlling the speed of the fan.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 vehicles vents.