Windshield Wipers

The windshield wipers operate only when the ignition is in ACCESSORY or ON.

The SASM monitors the wiper/washer switch inputs and sends the wiper/washer switch data to the BCM through the LIN 1 (shared with the headlamp switch). Based on the input, the BCM sends the requested wiper speed data on the LIN 8 to the driver side windshield wiper motor. The driver side windshield wiper motor then coordinates the wiper operation with the passenger side windshield wiper motor (using an isolated communication circuit between the two of them) to prevent interference between the windshield wipers while they are operating.

The BCM also receives a second input through a fail-safe circuit from the SASM. This fail-safe circuit makes sure the windshield wipers function in the event a LIN 1 circuit communication failure occurs between the SASM and the BCM. If a failure occurs on the LIN 1, the wipers operate at LOW speed when the wiper/washer switch is in any position other than OFF.

If a communication failure occurs on the LIN 8 circuit between the BCM and the windshield wiper motor, the windshield wipers operate for 5 minutes at high speed, 5 minutes at low speed, 5 minutes at an intermittent timing, and then turn off.

The wiper motor has a thermal protection strategy which disables the wiper motor when travel of the wiper arms is impeded by ice/snow and or excessive resistance as the result of operation on a dry windshield. The wipers may slow to a lower speed before being commanded off when a high friction situation/concern exists. It may be necessary to disconnect and then reconnect the battery after the repair to enable the wiper operation.