Automatic Climate Controls

DESCRIPTION

The Blower Motor control circuit consists of the following components: Blower Motor, Heating Ventilation and Air Conditioning (HVAC) Programmer, Blower Control Module, Heater and A/C Control Assembly and Steering Wheel Controls (if equipped).

OPERATION

The Blower's speed is determined by the voltage applied to the motor. At low Blower Motor speeds, the applied voltage is about 4 volts. As the voltage increases, the Blower Motor speed increases until the maximum Blower speed is reached. At maximum speed, the applied voltage is battery voltage.

Blower speed is controlled by the HVAC Programmer from temperature signal inputs and the operation mode of the Air Conditioning System. The system's driver selected operation mode is communicated to the HVAC Programmer from the Heater and A/C Control Assembly and Steering Wheel Controls (if equipped) through the E & C Data Line.

The Blower speed output from the HVAC Programmer is a continuously variable voltage. At minimum blower speed, the output is 2-3 volts. At maximum Blower speed, the output is 6-8 volts.

The output signal from the HVAC Programmer is input to the Blower Control Module. An amplifier and driver circuit in the Blower Control Module supplies between 4 volts and battery voltage to the Blower Motor. This same voltage is used as a feedback signal to the HVAC Programmer, which allows precise Blower Motor speed control.