Auxiliary Blower Motor Control Processor
WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The auxiliary blower motor control processor controls the speed of the blower motor by increasing or decreasing the voltage drop on the ground side of the auxiliary blower motor. The auxiliary HVAC control module or rear seat audio module (RSA) provides a voltage signal to the auxiliary blower motor control processor over the auxiliary blower motor speed control circuit. As the requested blower speed increases, the auxiliary HVAC control module or rear seat audio module (RSA) increases the amount of time that the speed signal is modulated to ground. As the requested blower speed decreases, the auxiliary HVAC control module or rear seat audio module (RSA) decreases the amount of time that the signal is modulated to ground.