Electronic A/C

BLOWER CONTROLS CIRCUIT OPERATION
The speed of the Blower Motor is determined by the voltage applied to the motor. At low blower speeds the applied voltage is about 4 volts. As the voltage is increased, the blower speed increases until maximum blower speed is reached at 12 volts.

CONTROL ASSEMBLY
The speed at which the blower runs is determined by the Heater & A/C Control Assembly from temperature signal inputs and the operating mode of the Air Conditioning System. The Heater & A/C Control Assembly accepts input requests from the driver by the front panel push-button.

BLOWER SPEED
The blower speed output from the Heater & A/C Control Assembly is a continuously variable voltage, proportional to blower speed. At minimum blower speed the output is 0.5 volts and at maximum blower speed it is about 7 volts. Medium blower speed is 4 volts.

The blower speed output signal is an input to the Heater and A/C Blower Module. An amplifier and driver circuit in the Heater and A/C Power Module supplies voltage between 4 and 12 volts to Blower Motor according to the blower speed input signal.

The voltage at the Blower Motor is fed back to the Heater & A/C Control Assembly at the blower feedback signal input terminal to allow precise speed control of the blower by the circuits in the Heater & A/C Control Assembly.