Principles of Operation (How Does It Work?)

Front Wiper and Washers
The multifunction switch controls the front wiper/washer portion and is wired to the GEM. When the switch is moved to the desired position the GEM processes this information and energizes one of two relay coils which control the front wiper motor speeds. In order to achieve high speed operation, both relays are energized. The GEM will respond to the wiper switch inputs only when the ignition is in RUN or ACC. The front washer pump relay is hard-wired to the GEM which will actuate the pump when the front wiper/washer switch portion of the multifunction switch is engaged, for up to 10 seconds.

Intermittent Wipers
The intermittent wiper speed control allows one of seven delay periods between each wiper swipe. The multifunction switch controls delay by resistors within the switch. This signal is sent to the GEM. The GEM then activates the wiper lo/hi relay at a chosen time interval specified by the multifunction switch. When the relay is activated the wiper motor will operate.

Rear Wiper and Washer
The rear wiper and washer is controlled by the rear wash/wiper switch. The switch contains an internal module which activates the rear wiper and washer. When the rear wiper is selected a ground signal to the rear wiper motor causes the motor to activate. When the washer is selected the switch will send a ground signal to the rear washer pump causing it to operate also activating the rear wiper motor.