Commander 2WD V8-4.7L (2008)
Wiper Motor: Description and Operation
Wiper Module
Description
DESCRIPTION
The front wiper module is secured to the cowl plenum panel beneath the cowl plenum cover/grille panel. The ends of the wiper pivot shafts protrude
through dedicated openings in the cowl plenum cover/grille panel to drive the wiper arms and blades and are the only visible components of the front
wiper module.
The front wiper module consists of the following major components:
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Bracket - The wiper module bracket (1) consists of a long tubular steel main member that has a stamped pivot bracket formation (5) near each
end where the two wiper pivots are secured. The wiper module bracket is secured within the cowl plenum by two screws and a stud and nut
through three rubber insulators (4). A stamped steel mounting plate (7) for the wiper motor (6) is secured with welds near the center of the main
member.
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Crank Arm - The wiper motor crank arm is a stamped steel unit with an internally splined hole on the driven end that is secured to the wiper
motor output shaft with a nut, and has a ball stud secured to the drive end to accept the wiper linkage. The crank arm is serviced only as a unit with
the front wiper motor.
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Linkage - A stamped steel drive link (8) connects the wiper motor crank arm to the passenger side wiper pivot lever arm (3), and a connecting
link (2) connects the passenger side pivot lever arm to the driver side pivot lever arm. Each link has a plastic socket-type bushing on each end. The
socket-type bushing on each link is snap-fit over a ball stud. There are two ball studs on the passenger side pivot lever arm and one each on the
motor crank arm and the driver side pivot lever arm.
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Motor - The wiper motor is secured with three screws to the motor mounting plate near the center of the wiper module bracket. The wiper motor
output shaft passes through a hole in the mounting plate, 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 Positive Temperature Coefficient (PTC)
circuit breaker. The front wiper motor with crank arm are serviced independently from the remainder of the front wiper module.
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Pivots - The two front wiper pivots are secured to the ends of the wiper module bracket. The lever arms that extend from the top of the pivot
shafts have ball studs on them. there are two ball studs on the passenger side lever arm and a single ball stud on the driver side lever arm. The
upper end of each pivot shaft where the wiper arms will be fastened is tapered and serrated with a threaded stud formation at the tip.
The front wiper module cannot be adjusted or repaired. The front wiper motor and crank arm is serviced independent of the front wiper module. If any
other component of the module is ineffective or damaged, the entire front wiper module unit must be replaced.
Operation
OPERATION
The front wiper module operation is controlled by the battery current inputs received by the wiper motor through the wiper on/off and wiper high/low
relays. 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 driven 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.
