Grand Cherokee 4WD L6-242 4.0L VIN S MFI (1993)
Control Module HVAC: Description and Operation
BLOWER MOTOR POWER MODULE
Models equipped with the optional Automatic Temperature Control (ATC) system have a blower motor power module. The power module allows
infinitely variable blower motor speeds. The power module is mounted to the heater-A/C housing, under the instrument panel and just inboard of the
blower motor, in the same location used for the blower motor resistor on manual temperature control systems. It can be accessed without removing any
other components.
The power module output to the blower motor can be controlled manually by using the blower motor switch knob on the ATC heater-A/C control panel,
or automatically by the circuitry of the ATC controller. In either case, the ATC controller sends the correct pulse width modulated signal to the power
module to obtain the selected or programmed blower motor speed
The power module cannot be repaired and, if faulty or damaged, it must be replaced.
