Rear Wiper System Malfunction

Rear Wiper System Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The rear wiper is controlled based on an input from the rear wiper/washer portion of the multifunction switch. When closed, the wiper ON and wiper DELAY switches provide a unique voltage signal to the rear window wiper motor indicating the desired speed. Each switch has a unique resistor that drops the voltage to a specified value which is interpreted by the rear window wiper motor as ON or DELAY. The rear wiper motor receives B+ voltage from the I/P fuse block and accessory voltage from the BCM.

Circuit/System Verification

1. Command the rear wiper ON using the rear wiper switch. The rear wiper should activate.

^ If the rear wiper does not activate, refer to Rear Wiper Malfunction

2. Command the delay rear wiper ON using the rear wiper delay switch. The rear wiper should activate in the delay mode.

^ If the delay rear wiper does not activate, refer to Rear Wiper Delay Malfunction.

Circuit/System Testing

Rear Wiper Malfunction
1. Ignition OFF, disconnect the harness connector X1 at the multifunction switch.
2. Ignition ON, verify a test lamp illuminates between the ignition circuit terminal 4.

^ If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal, refer to Power Mode Mismatch. Power Mode Mismatch

3. Ignition OFF, connect the harness connector at the multifunction switch. Disconnect the harness connector at the rear window wiper motor.
4. Test for less than 20 ohms of resistance between the ground circuit terminal B and ground.

^ If greater than the specified range, test the ground circuit for an open/high resistance.

5. Ignition ON, verify a test lamp illuminates between the B+ circuit terminal A and ground.

^ If the test lamp does not illuminate, test he B+ circuit for an open/high resistance.

6. Verify a test lamp illuminates between the ignition circuit terminal E and ground.

^ If the test lamp does not illuminate, test he ignition circuit for a short to ground or an open/high resistance.

7. Rear wiper switch in the ON position, test for B+ between the signal circuit terminal D and ground.

^ If less than the specified value, test the signal circuit for an open/high resistance. If the circuit tests normal, test or replace the multifunction switch.

8. If all circuits test normal, test or replace the rear window wiper motor.

Rear Wiper Delay Malfunction
1. Ignition OFF, disconnect the harness connector at the rear window wiper motor.
2. Rear wiper switch in the DELAY position, test for B+ between the signal circuit terminal D and ground.

^ If less than the specified value, test the signal circuit for an open/high resistance. If the circuit tests normal, test or replace the multifunction switch.

3. If all circuits test normal, test or replace the rear window wiper motor.

Component Testing

Multifunction Switch
1. Ignition OFF, disconnect the X1 harness connector multifunction switch.
2. With the rear wiper switch in the OFF, test for infinite resistance between the ignition terminal 4 and the signal terminal 5.

^ If not the specified value, replace the multifunction switch.

3. With the rear wiper switch in the ON position, test for 2000-2400 ohms of resistance between the ignition terminal 4 and the signal terminal 5.

^ If not within the specified range, replace the multifunction switch.

4. With the rear wiper switch in the DELAY position, test for 650-800 ohms of resistance between the ignition terminal 4 and the signal terminal 5.

^ If not within the specified range, replace the multifunction switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Turn Signal Multifunction Switch Replacement
* Rear Window Wiper Motor Replacement (Acadia) Rear Window Wiper Motor Replacement (Enclave) Rear Window Wiper Motor Replacement (OUTLOOK)