Rear Wiper Motor - Operation

REAR

The rear wiper motor operation is controlled by the Body Control Module (BCM), which uses relays soldered onto the BCM printed circuit board to control rear wiper system operation for energizing or de-energizing the rear wiper motor. The BCM uses internal programming, hard wired inputs received from the right (wiper) multi-function switch and the rear wiper motor park switch as well as electronic messages received over the Controller Area Network (CAN) data bus to provide the rear wiper and washer system operating modes.

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 electronic control logic circuitry of the BCM, depending upon the position of the rear wiper blade on the liftgate glass. This input allows the electronic logic circuits of the BCM 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.

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 converts the rotary output of the wiper motor to the back and forth wiping motion of the rear wiper arm and blade on the liftgate glass.

The hard wired inputs and outputs of the rear wiper motor may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the rear wiper motor or the electronic controls or communication between other modules and devices that provide some features of the rear wiper and washer system. The most reliable, efficient, and accurate means to diagnose the rear wiper motor or the electronic controls and communication related to rear wiper motor operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.