Buick Regal: Rear Washer System Malfunction

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

1. Rear Washer Inoperative
2. Rear Washer Always ON

Circuit/System Description

The windshield washer pump is controlled by the body control module (BCM) via a printed circuit board (PCB) relay. The BCM monitors the rear windshield wiper/washer switch signal circuit and when rear washer activation is requested, the BCM applies voltage through the rear window washer pump relay control circuit. With the relay energized, fused battery voltage is applied through the switch contacts of the relay and the windshield washer pump control circuit to activate the windshield washer pump.

Reference Information

Schematic Reference

Wiper/Washer Wiring Schematics

Connector End View Reference

COMPONENT CONNECTOR END VIEWS - INDEX

Description and Operation

Wiper/Washer System Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Verification

1. Ignition ON.

2. Verify the scan tool Rear Washer Relay Command parameter changes between Active and Inactive when cycling the rear washer switch ON and OFF.

• If the parameter does not change

Refer to Circuit/System Testing - Rear Wiper/Washer Switch Malfunction

• Go to next step: If the parameter changes

3. Verify the Rear Window Washer turns ON and OFF when commanding the Rear Washer Relay Active with a scan tool.

• If the Rear Window Washer does not turn ON and OFF

Refer to Circuit/System Testing - Rear Washer Pump Malfunction

• Go to next step: If the Rear Window Washer turns ON and OFF

4. All OK.

Circuit/System Testing

Rear Wiper/Washer Switch Malfunction

1. Ignition OFF and all vehicle systems OFF, disconnect the X3 harness connector at the S82 Windshield Wiper/Washer Switch. It may take up to 2 min for all vehicle systems to power down.

2. Test for less than 10 Ω between the low reference circuit terminal 1 and ground.

• If 10 Ω or greater

1. Ignition OFF.
2. Test for less than 2 Ω in the low reference circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K9 Body Control Module.

• Go to next step: If less than 10 Ω

3. Ignition ON.

4. Test for greater than 8 V between the signal circuit terminal 5 and ground.

• If less than 8 V

1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module.
2. Test for infinite resistance between the signal circuit and ground
   • If less than infinite resistance, repair the short to ground on the circuit.
   • Go to next step: If infinite resistance
3. Test for less than 2 Ω in the signal circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K9 Body Control Module.

• Go to next step: If 8 V or greater

5. Ignition OFF, disconnect the X2 harness connector at the K9 Body Control Module, ignition ON.

6. Test for less than 1 V between the S82 Windshield Wiper/Washer Switch signal circuit terminal 5 and ground.

• If 1 V or greater

Repair the short to voltage on the circuit.

• Go to next step: If less than 1 V

7. Test or replace the S82 Windshield Wiper/Washer Switch.

Rear Washer Pump Malfunction

1. Ignition OFF, and all vehicle systems OFF. Disconnect the X1 harness connector at the X50A Fuse Block - Underhood. It may take up to 2 min for all vehicle systems to power down.

2. Test for less than 10 Ω between the X50A Fuse Block - Underhood ground circuit terminal 53 and ground.

• If 10 Ω or greater

1. Test for less than 2 Ω in the ground circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, repair the open/high resistance in the ground connection.

• Go to next step: If less than 10 Ω

3. Test for infinite resistance between each control circuit listed below and ground:

1. Terminal 2 X1
2. Terminal 1 X1

• If less than Infinite resistance

Repair the short to ground on the circuit.

• Go to next step: If infinite resistance

4. Disconnect the harness connector at the G24 Windshield Washer Pump and connect the X1 harness connector at the X50A Fuse Block - Underhood.

5. Test for less than 10 Ω between the control circuit terminal 1 and the control circuit terminal 2.

• If 10 Ω or greater

1. Ignition OFF, disconnect the X1 harness connectors at the X50A Fuse Block - Underhood.
2. Test for less than 2 Ω in each of the control circuits listed below end to end:
   • Terminal 2
   • Terminal 1
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the X50A Fuse Block - Underhood.

• Go to next step: If less than 10 Ω

6. Connect a test lamp between the control circuit terminal 1 and the control circuit terminal 2, ignition ON.

7. Verify the test lamp does NOT turn ON and OFF when commanding the Rear Window Washer Relay Active and Inactive with a scan tool.

• If the test lamp turns ON and OFF

Test or replace the G24 Windshield Washer Pump.

• Go to next step: If the test lamp does not turn ON and OFF

8. Ignition OFF, connect the harness connector at the G24 Windshield Washer Pump, ignition ON.

9. Verify the G24 Windshield Washer Pump is NOT activated.

• If the G24 Windshield Washer Pump is activated

1. Ignition OFF, disconnect the harness connector at the G24 Windshield Washer Pump, ignition ON.
2. Test for less than 1 V between each of the control circuits listed below and ground:
   • Terminal 1
   • Terminal 2
   • If 1 V or greater, repair the short to voltage on the circuit.
   • If less than 1 V, replace the G24 Windshield Washer Pump.

• Go to next step: If the G24 Windshield Washer Pump is not activated

10. Ignition OFF, disconnect the X5 harness connector at the K9 Body Control Module, ignition ON.

11. Verify the G24 Windshield Washer Pump is NOT activated.

• If the G24 Windshield Washer Pump is activated

1.  Ignition OFF, disconnect the X2 harness connector at the X50A Fuse Block - Underhood, ignition ON.
2. Test for less than 1 V between the X50A Fuse Block - Underhood control circuit terminal 52 and ground.
   • If 1 V or greater, repair the short to voltage on the circuit.
   • If less than 1 V, replace the X50A Fuse Block - Underhood.

• Go to next step: If the G24 Windshield Washer Pump is not activated

12. Connect a 10 A fused jumper wire between the control circuit terminal 11 X5 and B+.

13. Verify the G24 Windshield Washer Pump activates.

• If the G24 Windshield Washer Pump does not activate

1. Ignition OFF, remove the jumper wire, disconnect the X2 harness connector at the X50A Fuse Block - Underhood.
2. Test for infinite resistance between the X50A Fuse Block - Underhood control circuit terminal 52 X2 and ground.
   • If less than infinite resistance, repair the short to ground on the circuit.
   • Go to next step: If less than infinite resistance
3. Test for less than 2 Ω in the control circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, test or replace the X50A Fuse Block - Underhood.

• Go to next step: If the G24 Windshield Washer Pump activates

14. Replace the K9 Body Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Engine Wiring Harness Junction Block Replacement (LTG) Engine Wiring Harness Junction Block Replacement (LGX)
• Windshield Washer Pump Replacement
• Windshield Wiper and Washer Switch Replacement
• Control Module References for Body Control Module replacement, programming and setup

READ NEXT: