MODULE-POWER-BLOWER MOTOR
DESCRIPTION
A blower motor power module is used on this model when it is equipped with the automatic temperature control (ATC) heating-A/C system. Models equipped with the manual temperature control (MTC) heating-A/C system use a blower motor resistor, instead of the blower motor power module (refer to 24 - HEATING & AIR CONDITIONING/CONTROLS/RESISTOR-BLOWER MOTOR - DESCRIPTION).
The blower motor power module is mounted to the rear of the HVAC housing, directly behind the glove box. The blower motor power module consists of a molded plastic mounting plate with two integral connector receptacles (1). Concealed behind the mounting plate is the power module electronic circuitry and a large finned heat sink (2).
The blower motor power module is accessed for service by removing the glove box.
OPERATION
The blower motor power module is connected to the vehicle electrical system through a dedicated lead and connector of the HVAC wire harness. A second connector receptacle receives the wire harness connector from the blower motor. The blower motor power module allows the microprocessor-based automatic temperature control (ATC) A/C-heater control to calculate and provide infinitely variable blower motor speeds based upon either manual blower switch input or the ATC programming using a pulse width modulated (PWM) circuit strategy.
The PWM voltage is applied to a comparator circuit which compares the PWM signal voltage to the blower motor feedback voltage. The resulting output drives the power module circuitry, which provides a linear output voltage to change or maintain the desired blower speed.
The blower motor power module is diagnosed using a scan tool (refer to 24 - HEATING & AIR CONDITIONING - DIAGNOSIS AND TESTING - HEATING AND A/C SYSTEMS and to 24 - HVAC Electrical Diagnostics for more information).
The blower motor power module cannot be adjusted or repaired and must be replaced if found inoperative or damaged.
REMOVAL
WARNING: Disable the airbag system before attempting any steering wheel, steering column, or instrument panel component diagnosis or service. Disconnect and isolate the negative battery (ground) cable, then wait two minutes for the airbag system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the airbag system. Failure to take the proper precautions could result in accidental airbag deployment and possible personal injury or death.
WARNING: The heat sink for the blower motor power module may get very hot during normal operation. If the blower motor was turned on prior to servicing the blower motor power module, wait five minutes to allow the heat sink to cool before performing diagnosis or service. Failure to take this precaution can result in possible personal injury.
NOTE: LHD model shown. RHD model similar.
1. Disconnect and isolate the negative battery cable.
2. On LHD models, remove the glove box from the instrument panel (refer to 23 - BODY/INSTRUMENT PANEL/GLOVE BOX - REMOVAL).
3. On RHD models, remove the instrument panel silencer from the passenger side of the instrument panel (refer to 23 - BODY/INSTRUMENT PANEL/INSTRUMENT PANEL SILENCER - REMOVAL).
4. Disconnect the two wire harness connectors (1) from the blower motor power module (2).
5. Remove the two screws (3) that secure the blower motor power module to the HVAC housing (4).
6. Remove the blower motor power module from the HVAC housing.
INSTALLATION
NOTE: LHD model shown. RHD model similar.
1. Position the blower motor power module (2) into the HVAC housing (4).
2. Install the two screws (3) that secure the blower motor power module to the HVAC housing. Tighten the screws to 2 N·m (17 in. lbs.).
3. Connect the two wire harness connectors (1) to the blower motor power module.
4. On LHD models, install the glove box into the instrument panel (refer to 23 - BODY/INSTRUMENT PANEL/GLOVE BOX - INSTALLATION).
5. On RHD models, install the instrument panel silencer onto the passenger side of the instrument panel (refer to 23 - BODY/INSTRUMENT PANEL/INSTRUMENT PANEL SILENCER - INSTALLATION).
6. Reconnect the negative battery cable.