Blower Motor: Description and Operation

A/C Blower Controls Schematic:

DESCRIPTION AND OPERATION
Blower speed is determined by the Body Computer Module (BCM) for the temperature data input and the operating mode of the Air Conditioning System. The Climate Control Panel (CCP) accepts input requests from the driver via the front panel push-button. The input signals determine the operating mode for the Climate Control System and are sent to the BCM over the data line (Circuit 718).

The output from the BCM at Terminal A9 is variable. If voltage is less than 2 volts, blower speed decreases. If voltage is between 2-3 volts, blower speed remains the same. If voltage is greater than 3 volts, blower speed increases. The Electronic Climate Control (ECC) Power Module supplies voltage to the Blower Motor (Circuit 65) according to the input signal at terminal C2/B.

Feedback voltage from the Blower Motor is applied to the BCM (Circuit 761) to allow precise speed control by the circuits in the BCM.