Wiper Control Module: Description and Operation

Fig.17 Front Wiper Module:

FRONT WIPER MODULE
The front wiper module is secured with screws to the cowl top panel and concealed within the cowl plenum area beneath the cowl plenum cover/grille panel. The ends of the wiper pivot shafts that protrude through dedicated openings in the cowl plenum cover/grille panel to drive the wiper arms and blades are the only visible components of the front wiper module. The front wiper module consists of the following major components:
- Bracket - The front wiper module bracket consists of a long tubular steel main member that has a stamped pivot bracket formation near each end where the two wiper pivots are secured. A stamped steel mounting plate for the wiper motor is secured with welds near the center of the main member. A reinforcement and stud plate with a rubber-isolated mounting bracket extends from the cowl plenum side of the dash panel to the motor mounting plate to provide additional support.
- Crank Arm - The front wiper motor crank arm is a stamped steel unit with a slotted hole on the driven end that is secured to the wiper motor output shaft with a nut, and a ball stud secured to the drive end.
- Linkage - The two front wiper linkage members are each constructed of stamped steel. A connecting link with a plastic socket-type bushing in the right end, and a plastic sleeve-type bushing in the left end, is fit over the pivot ball studs to join the two pivots.
The wiper drive link has a plastic socket-type bushing on each end. One end of the drive link is snap-fit over the exposed end of the longer left pivot ball stud, while the other end is snap-fit over the ball stud on the wiper motor crank arm.
- Motor - The front wiper motor is secured with three screws to the motor mounting plate near the center of the wiper module bracket and is protected by a rubber boot. The wiper motor output shaft passes through a hole in the module bracket, where a nut secures the wiper motor crank arm to the motor output shaft. The two-speed permanent magnet wiper motor features an integral transmission, an internal park switch, and an internal automatic resetting circuit breaker.
- Pivots - The two front wiper pivots are secured to the ends of the wiper module bracket. The crank arms that extend from the bottom of the pivot shafts each have a ball stud on their end. The left pivot ball stud is longer than the ball stud on the right pivot. The upper end of each pivot shaft where the wiper arms will be fastened each has an externally serrated drum secured to it.
The front wiper module cannot be adjusted or repaired. If any component of the module is faulty or damaged, the entire front wiper module unit must be replaced. The reinforcement bracket and stud plate are available for service replacement.

The front wiper module operation is controlled by the vehicle operator through battery current inputs received by the wiper motor from the right multi- function switch on the steering column. The wiper motor speed is controlled by current flow to either the low speed or the high speed set of brushes. The 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 the wiper park switch sense circuit to ground or to battery current, depending upon the position of the wipers on the glass. This feature allows the motor to complete its current wipe cycle after the wiper system has been turned OFF, and to park the wiper blades in the lowest portion of the wipe pattern. The automatic resetting circuit breaker protects the motor from overloads. The wiper motor crank arm, the two wiper linkage members, and the two wiper pivots mechanically convert the rotary output of the wiper motor to the back and forth wiping motion of the wiper arms and blades on the glass.

Fig.21 Rear Wiper Module:

REAR WIPER MODULE
The rear wiper module is concealed within the liftgate, below the liftgate glass and behind the liftgate trim panel. The end of the motor output shaft that protrudes through the liftgate outer panel to drive the rear wiper arm and blade is the only visible component of the rear wiper module. A rubber gasket, a plastic bezel with an integral washer hose in-line connector, and a nut seals and secures the motor output shaft to the liftgate outer panel. The rear wiper module consists of the following major components:
- Bracket - The rear wiper module bracket consists of a stamped steel mounting plate for the wiper motor that is secured with screws to the wiper motor and to the liftgate inner panel.
- Motor - The single-speed permanent magnet rear wiper motor is secured with screws to the rear wiper module bracket. The wiper motor includes an integral transmission, a motor output shaft, the rear wiper module circuitry, a diode, and the rear wiper motor park switch.

The rear wiper module cannot be adjusted or repaired. If any component of the module is faulty or damaged, the entire rear wiper module unit must be replaced. The motor output shaft gasket, bezel, and nut are available for service replacement.

The rear wiper module operation is controlled by the vehicle operator through battery current inputs received by the rear wiper module circuit board from the rear wiper and washer switch on the instrument panel. The wiper blade cycling is controlled by the rear wiper module circuit board, which controls current flow to the wiper motor brushes. The 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 the wiper motor brush to the module circuit board output or to a fused ignition switch output (run) circuit, depending upon the position of the wiper on the glass. This feature allows the motor to complete its current wipe cycle after the wiper system has been turned OFF, and to park the wiper blade in the lowest portion of the wipe pattern. An internal diode protects the module circuit board from feedback through the park switch when the switch is closed to the fused ignition switch output (run) circuit. The 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.