Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Rear WPR Relay B+ | 1 | 1 | -- | -- |
Rear Wiper Washer Switch Supply Voltage | 2 | 1 | 1 | -- |
Rear Window Wiper Switch Signal | 2 | 1 | 1 | -- |
Rear Wiper Motor Park Signal | 1 | 2 | 1 | -- |
Rear Window Wiper Motor Control | 1 | 1 | 2 | -- |
Rear WPR Relay Ground | -- | -- | 2 | -- |
Rear Window Wiper Motor Ground | -- | 1 | -- | -- |
Rear Window Wiper Washer Switch Ground | -- | 1 | -- | -- |
1.Rear Window Window Wipers Inoperative. 2. Rear Window Wipers ON at all times | ||||
Circuit/System Description
Battery positive voltage is supplied through the REAR WPR fuse to the coil and switched sides of the REAR WPR relay. When the BCM receives a signal from the Rear Wiper/Washer switch, the BCM provides ground to the coil side of the relay and providing a path for voltage to the Rear Window Wiper motor, activating the motor. The Rear Window Wiper motor receives a path to ground from G402. Except for when it is in the Wash mode, the rear window wiper wipes the rear window at delay time intervals.
Except for when it is in the Wash mode, the rear window wiper wipes the rear window at delay time intervals. With the rear wiper system activated, the length of time between wipes can be adjusted by selecting any one of the 3 delay speed settings of the windshield wiper switch. During the Wash mode, if the rear washer switch is momentarily turned to ON, the rear wiper will wipe the rear window 3-5 times and then park. However, if the rear washer switch is held to ON, the rear window wipers will continue to operate until the switch is released. While the delay speed of both the front and rear wipers is adjusted by the windshield wiper switch selections, the delay time intervals of the rear wiper are not synchronized with the delay time intervals of the front wipers. The rear wiper should stop at the Park position anytime the rear wiper is not wiping. However, if the ignition switch is turned OFF while the rear wiper is wiping, the wiper will stop at its current location on the glass.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Wiper/Washer System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Ignition ON, liftgate closed, verify the liftgate ajar message is not displayed on the driver information center.
- Command the rear wiper ON using the rear wiper/washer switch. The rear wiper should activate.
| ⇒ | If the liftgate ajar message is displayed refer to Liftgate Ajar Indicator Malfunction |
Circuit/System Testing
- Ignition OFF, disconnect the Rear WPR Relay.
- Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 30 and ground.
- Verify that a test lamp illuminates between the B+ circuit terminal 87 and ground.
- Verify that a test lamp illuminates between the B+ circuit terminal 86 and ground.
- Disconnect the harness connector at the rear window wiper motor.
- Test for less than 10 Ω between the rear window wiper motor ground circuit terminal 1 and ground
- Connect the harness connector at the rear wiper motor.
- Connect a 15 A fused jumper wire between the B+ circuit terminal 87 and the control circuit terminal 30. Verify the rear window wiper motor is activated.
- Connect a test lamp between the B+ circuit terminal 86 and the control circuit terminal 85.
- Command the Rear WPR Relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If all circuits test normal, test or replace the Rear WPR Relay.
| ⇒ | If the test lamp illuminates, test the control circuit for a short to voltage. |
| ⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 30 for a short to ground. If the circuit tests normal, test or replace the REAR WPR Relay |
| ⇒ | If the test lamp does not illuminate, test the B+ circuit for an open/high resistance. |
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | If the rear window wiper motor does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the rear window wiper motor. |
| ⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM. |
| ⇒ | If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM. |
Component Testing
Rear Wiper/Washer Switch
- With the rear wiper switch in the open position, test for infinite resistance between the ground terminal 3 and the signal terminal 5.
- With the rear wiper switch in the closed position, test for less than 2 ohms of resistance between the ground terminal 3 and the signal terminal 5.
| ⇒ | If not the specified value, replace the rear wiper/washer switch. |
| ⇒ | If not within the specified range, replace the rear wiper/washer switch. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure
| • | Control Module References for BCM replacement, setup, and programming |
