Air Speed - Auxiliary

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A rocker type switch on the RSA control module provides the operator the ability to select several blower speeds. The RSA control module uses a bar graph to indicate the selected blower speed. The auxiliary blower motor control processor supplies a 5-volt reference to the auxiliary HVAC control module on the auxiliary blower motor speed control circuit. The auxiliary HVAC control module pulls the 5-volt reference low towards ground to provide a blower motor speed signal. As the voltage decreases the blower speed increases. Power and ground are provided to the auxiliary blower motor control processor through the battery positive voltage and ground circuits. The auxiliary HVAC control module can not request A/C operation from the powertrain control module (PCM).