General Information

The blower motor forces outside air into the vehicle's interior. The vehicle operator determines the blower motors speed by toggling the blower motor switch manually or by using the automatic mode. The blower motor will always operate at some speed as long as the HVAC control module (IPM) 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 IPM.

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 circuit.

When any blower speed is selected, whether manual or automatic, the blower motor control processor will control blower motor speeds based on voltage signals from the IPM. Once received by the HVAC control module, a 5-volt Pulse Width Modulated (PWM) signal is sent to the blower motor control processor 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 signal is increased. The blower motor control processor interprets the PWM signal and varies the ground on the blower motor control circuit internally. An open circuit, short to ground or short to battery on the blower motor speed control circuit will disrupt the PWM signal and cause the blower motor to not operate. The blower motor flange ground circuit is used to limit radio frequency interference and does not affect blower operation. In automatic Operation, the IPM will determine what blower speed is necessary in order to achieve or maintain a desired temperature. Toggling the blower button manually also activates the VF display for the blower speed selected.