General Information

The blower motor forces ambient air into the vehicle's interior. The vehicle operator determines the blower motor's speed by turning the blower motor switch manually. The blower motor will only operate if the blower motor switch is in any position other than OFF, as long as the ignition switch is in the RUN position. The blower motor and mode switches are located within the HVAC control module.

Power is provided to the blower motor from the blower motor control processor through the blower motor supply voltage circuit. The blower motor control processor receives power from the rear fuse block through the battery positive voltage circuit. Ground is provided by the blower motor control processor and ground circuits.

The HVAC control module receives power from the rear fuse block on the ignition 3 voltage circuit and battery positive voltage circuit. The ground circuits provides ground for the module.

The driver can control the blower speed by turning the blower motor switch. A 5 volt pulse width modulated (PWM) signal is sent from the HVAC control module to the blower motor control processor. The PWM signal is sent on the blower motor speed control circuit. When a low blower speed is requested, the PWM signal is reduced. When a higher blower speed is requested, the PWM is increased. An open, short to voltage or short to ground on the blower motor speed control circuit will disrupt the PWM signal. Without the PWM signal, the blower motor will not operate.

The blower motor supply voltage circuit is used to send a 12 volt signal from the blower motor control processor to the blower motor. The blower motor control processor regulates the ground on the blower motor control circuit. This regulates the speed of the blower motor. The blower motor flange ground circuit is used to limit radio frequency interference and does not affect blower operation.

The blower motor will be slowed when the vehicle experiences high electrical loads. This is done automatically. The blower will remain at this speed for the duration of the ignition cycle.