Cutlass L4-138 2.3L VIN A FI HP (1990)
Blower Motor: Description and Operation
Manual A/C
VARIABLE SPEED MOTOR
The Blower Motor is a variable speed motor. The higher the voltage applied to the motor, the faster the speed.
BLOWER MOTOR OFF
With the HVAC Control Assembly in "OFF," voltage is applied to the Low Blower Relay coil through the YEL (770) wire. The relay operates, its
contacts open, and voltage to the Blower Switch is removed.
BLOWER MOTOR RESISTOR
When any other mode except "OFF" is selected, the Blower Motor Relay is de-energized and voltage is applied to the Blower Switch and Blower
Motor Resistors.
LOW SPEED
When the Blower Switch is in "LO," voltage is applied through all three Blower Resistors to the relay contacts in the High Blower Relay and the
Blower Motor. The Blower Motor runs at low speed.
MEDIUM SPEEDS
As the Blower Switch is moved through positions "M1" and "M2," the switch bypasses some of the Blower Motor Resistors, allowing more voltage to
be applied to the Blower Motor, which will increase its speed.
HIGH SPEED
When the Blower Motor Switch is in "HI," voltage is applied through the ORN (52) wire to the coil of the High Blower Relay. The High Blower
Relay operates removing the Blower Motor Resistors from the circuit. Battery voltage is then applied directly to the Blower Motor through the Blower
Relay contacts. The motor runs at maximum speed.
