Wiper/Washer System Description

The body control module (BCM) controls wiper motor low speed operation, washer pump and high speed operation. The windshield wiper/washer switch supplies a Low or Ground on the signal circuits to the BCM for windshield wiper/washer operation. When WASH, MIST, DELAY, LOW, or HIGH is detected, the BCM energizes the WPR1 relay by suppling Low signal to the relay coil. This allows battery voltage from the FRT WPR fuse to flow through the relay switched input then through the contacts and out the relay switched output to the WPR2 relay switched contacts. Since the WPR2 relay switched contacts are normally closed to the low speed circuit of the windshield wiper motor, the motor will operate at low speed. For HI speed operation the BCM supplies the same Low signal to the WPR1 relay control circuit and also supplies a Low signal to the WPR2 relay control circuit. The WPR2 relays normally opened contacts are now in series with the current supplying WPR1 relay contacts. The WPR2 relay normally open contact at this point supply current to the wiper motors HI input.