Wiper Motor: Description and Operation

Wiper Motor:

The wiper motor is secured with three screws to a motor bracket integral to the wiper linkage module bracket located below the cowl top panel in the engine compartment. The wiper motor output shaft passes through a hole in the motor 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 Positive Temperature Coefficient (PTC) circuit breaker.

The wiper motor cannot be adjusted or repaired. If any component of the motor is faulty or damaged, the entire wiper motor unit must be replaced.

The wiper motor operation is controlled by the vehicle operator through battery current inputs received by the wiper motor from the wiper switch circuitry of the multi-function switch on the top of the steering column, and from the wiper relay on the fuse block underneath 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 automatic resetting circuit breaker protects the motor from overloads.

The park switch consists of a contact disc and three contacts. The contact disc is mechanically fastened to and rotated with a gear in the wiper motor transmission. Two input contacts alternately close the wiper park switch sense output circuit contact to ground or to battery current, depending upon the position of the wipers on the glass. This feature allows the intermittent wipe logic circuit to monitor the position and the cycles of the wiper motor to provide the intermittent wipe and wipe-after-wash modes, as well as allowing the motor to complete its current wipe cycle after the wiper system has been turned Off and park the wiper blades in the lowest portion of the wipe pattern.

The wiper motor may be diagnosed using conventional diagnostic tools and methods.