Circuit Description

The Body Control Module (BCM) monitors the voltage level on the supply voltage circuit of the Wiper 1 relay. The voltage level should be low while the Wiper 1 relay is de-energized. The voltage will be near system voltage when the BCM energizes the Wiper 1 relay. The supply voltage circuit of the Wiper 1 relay is shared with the signal circuit of the windshield wiper motor park switch internally in the BCM. The BCM monitors the signal circuit of the windshield wiper motor park switch to determine if the windshield wiper motor is operating when commanded. The voltage on the signal circuit of the windshield wiper motor park switch should be near system voltage while the wipers are active. This the result of the windshield wiper motor park switch being open. The voltage is pulled low when wipers are in or return to the PARK position. The windshield wiper motor park switch will be closed, pulling the circuit to ground.