Power Blower Motor Module
DESCRIPTION
| 1 - Molded Plastic Mounting Plate |
| 2 - Integral Wire Harness Connector Receptacles |
| 3 - Blower Motor Power Module Electronic Circuitry |
| 4 - Large-Finned Heat Sink |
The Heating, Ventilating and Air Conditioning (HVAC) system uses a blower motor power module to control the blower motor speed.
The blower motor power module is mounted to the HVAC housing, on the passenger side of the vehicle. The blower motor power module consists of a molded plastic mounting plate with integral wire harness connector receptacles. Concealed behind the mounting plate is the blower motor power module electronic circuitry and a large-finned heat sink.
The blower motor power module is accessed for service from underneath the instrument panel.
OPERATION
The blower motor power module is connected to the vehicle electrical system through a dedicated lead and connector of the instrument panel wire harness. A second lead and connector of the instrument panel wire harness is connected to the blower motor.
The blower motor power module allows the microprocessor-based A/C heater control to provide an infinite amount of blower motor speeds throughout its operating range, based upon blower switch input.
The A/C heater control system uses a Pulse Width Modulated (PWM) circuit strategy. 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 HEATING AND AIR CONDITIONING, DIAGNOSTIC CODE INDEX .
The blower motor power module cannot be adjusted or repaired and must be replaced if inoperative or damaged.