Circuit Description

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

The body control module (BCM) commands the Intermittent mode of the wipers by switching the front wiper relay control circuit to ground at regular timed intervals. This provides low speed operation of the wiper motor during single swipes of the wipers. Each time the BCM grounds the circuit, the FRT WIPER relay energizes, which closes the switch side contacts of the relay in order to apply battery positive voltage to the windshield wiper motor via the windshield wiper switch MIST/OFF/LOW signal circuit and windshield wiper motor low speed circuit. The BCM monitors the voltage on the front wiper relay control circuit in order to determine when a failure has occurred. When the FRT WIPER relay is energized, the voltage level on the front wiper relay control circuit should be near 0 volts. When the FRT WIPER relay is de-energized, the voltage level should be high, near system voltage.

Control of the wipers during LO or HIGH speed switch settings is direct wired from the windshield wiper washer switch to the wiper motor and is not under the control of the BCM.