Rear Wiper Washer System Malfunction

Rear Wiper Washer 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 washer is activated based on an input from the rear washer switch. When the wiper portion of the rear wiper/washer switch is closed, B+ is applied to the REAR/WSW relay indicating rear washer operation is requested. With B+ applied to the relay coil, the relay is energized and B+ is supplied to the washer pump.

Circuit/System Verification

1. Ignition ON, verify the rear wiper operates normally using the rear wiper switch.

^ If the rear wipers do not operate properly, refer to Windshield Wiper System Malfunction. Windshield Wiper System Malfunction

2. Operate the rear washers using the rear washer switch. The rear washer pump should activate.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the rear window wiper motor.
2. Install a test lamp between the control circuit terminal C and ground.
3. Ignition ON, command the rear washers ON and OFF using the rear washer switch. The test lamp should turn ON and OFF when changing between the commanded states.

^ If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, test or replace the multifunction switch.

^ If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the multifunction switch.

4. Ignition OFF, connect the harness connector at the rear window wiper motor. Disconnect the REAR/WSW relay.
5. Ignition ON, verify a test lamp does not illuminate between the control circuit terminal 87 and ground.

^ If the test lamp illuminates, test the control circuit for a short to voltage.

6. Ignition OFF, test for less than 5 ohms of resistance between the ground circuit terminal 86 and ground.

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

7. Ignition ON, verify a test lamp illuminates between the B+ circuit terminal 30 and ground.

^ If the test lamp does not illuminate, replace the I/P fuse block.

8. Install a test lamp between the control circuit terminal 85 and ground.
9. Command the rear washers ON and OFF using the rear washer switch. The test lamp should turn ON and OFF when changing between the commanded states.

^ If the test lamp is always ON, replace the I/P fuse block.

^ If the test lamp is always OFF, replace the I/P fuse block.

10. Ignition OFF, disconnect the harness connector at the rear window washer fluid pump.
11. Test for less than 20 ohms of resistance between the ground circuit terminal A and ground.

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

12. Connect the harness connector at the rear window washer fluid pump.
13. Connect a 20A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the rear window washer fluid pump is activated.

^ If the rear window washer fluid pump does not activate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the rear window washer fluid pump.

14. If all circuits test normal, test or replace the REAR/WSW relay.

Component Testing

Multifunction Switch
1. Ignition OFF, disconnect the X1 harness connector at the multifunction switch.
2. With the rear washer switch open, test for infinite resistance between the B+ terminal 4 and the control terminal 6.

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

3. With the rear washer switch closed, test for less than 2 ohms of resistance between the B+ terminal 4 and the control terminal 6.

^ If greater than the specified range, replace the multifunction switch.

Rear Window Washer Fluid Pump
1. Ignition OFF, disconnect the harness connector at the rear window washer fluid pump.
2. Install a 20A fused jumper wire between the control terminal B and 12 volts. Install a jumper wire between the ground terminal A and ground.
3. Verify the rear window washer fluid pump is activated.

^ If the rear window washer fluid pump does not activate, replace the rear window washer fluid pump.

Repair Instructions

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

* Rear Window Washer Pump Replacement (Acadia, Enclave) Rear Window Washer Pump Replacement (OUTLOOK)
* Turn Signal Multifunction Switch Replacement
* Instrument Panel Electrical Center or Junction Block Replacement