Commander 2WD V8-4.7L (2008)
Wiper Motor: Description and Operation
Wiper Motor
Description
REAR
The rear wiper motor (4) is concealed within the liftgate, below the liftgate glass and behind the liftgate inner trim panel. The end of the motor output
shaft (2) that extends through the liftgate outer panel to drive the rear wiper arm and blade is the only visible component of the rear wiper motor. A
rubber bezel and grommet is engaged within the output shaft hole of the liftgate outer panel and seals the output shaft where it passes through the panel.
An integral connector receptacle (3) connects the rear wiper motor to the vehicle electrical system through a dedicated take out and connector of the
liftgate wire harness. The rear wiper motor consists of the following major components:
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Bracket (5) - The rear wiper motor bracket consists of a molded plastic mounting plate for the wiper motor that is secured with screws to the
wiper motor housing, and through two screws with rubber isolators (1) to the liftgate inner panel.
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Electronic Controls - The rear wiper motor electronic controls include the rear wiper system electronic logic. The electronic controls for the
motor include an electronic speed control that speeds the wiper blade near the center of the glass, but slows the wiper blade during directional
reversals at each end of the wipe pattern and during wiper arm and blade off-the-glass parking for quieter operation.
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Motor - The single-speed permanent magnet rear wiper motor is secured to the rear wiper motor bracket. The wiper motor includes an integral
transmission, motor output shaft, an automatic resetting circuit breaker and the rear wiper motor park switch.
The rear wiper motor cannot be adjusted or repaired. If any component of the motor is ineffective or damaged, the entire rear wiper motor unit must be
replaced. The motor output shaft bezel and grommet, and the mounting nut are available for individual service replacement.
Operation
REAR
The rear wiper relay controls battery current flow to the rear wiper module logic circuit based upon control outputs from the Front Control Module
(FCM). The FCM uses internal programming and electronic messages received over the Controller Area Network (CAN) data bus from the
ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) to determine when to energize or de-energize the rear
wiper relay and to determine the selected rear wiper operating mode. The FCM provides hard wired signal outputs to the rear wiper module on two
circuits that indicate the selected operating mode and delay interval, which the rear wiper module uses as logic inputs to control rear wiper motor
operation.
The rear wiper motor park switch is a single pole, single throw, momentary switch within the wiper motor that is mechanically actuated by the wiper
motor transmission components. The park switch alternately closes and opens a path to ground for the rear wiper motor control circuit input to the wiper
motor electronic controls, depending upon the position of the rear wiper blade on the liftgate glass.
The motor control electronics also monitor a hard wired input from the liftgate flip-up glass ajar switch to determine whether the glass is opened or
closed. These inputs allow the electronic logic circuits to control all of the electronic features of rear wiper motor operation and to keep the motor
energized long enough to complete its current wipe cycle and park the wiper blade after the wiper system or the ignition switch has been turned OFF, or
when the liftgate flip-up glass has been opened.
The rear wiper motor is grounded at all times through a take out with an eyelet terminal connector in the body wire harness that is secured to a ground
location in the passenger compartment. The automatic resetting circuit breaker protects the motor from overloads. The rear wiper motor transmission
