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Rear Washer System Malfunction




Rear Washer System Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information






Circuit/System Description

When the Body Control Module (BCM) detects that the Rear Wiper/Wash switch has activated the momentary Wash switch, it activates a High Side Drive output which supplies battery to the coil of the rear washer pump relay. This energizes the relay, which switches battery power to the washer pump motor. The BCM will also activate continuous low speed windshield wipers as described above. This Washer and Wiper operation shall be continued so long as the switch remains active. Upon termination, the rear wash motor will be deactivated and the wiper shall move to its Park position and deactivate.

Reference Information

Schematic Reference

Wiper/Washer Schematics Electrical Diagrams

Connector End View Reference

Component Connector End Views Sunshade - Left Front

Description and Operation

Wiper/Washer System Description and Operation Description and Operation

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.

2. Verify the rear washer activates when the Rear Washer Relay Command is commanded On and Off with a scan tool.

• If the rear washer does not activate
Refer to Circuit/System Testing - Rear Washer Pump Circuit Test.

• If the rear washer activates

3. Refer to Circuit/System Testing - Rear Washer Switch Circuit Test.

Circuit/System Testing

Rear Washer Switch Circuit Test

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the S78 turn signal/multifunction switch. It may take up to 2 minutes for all vehicle systems to power down.

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

• If 10 ohms or greater

1. Ignition OFF, disconnect the X3 harness connector at the K9 body control module.

2. Test for less than 2 ohms in the low reference circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the K9 body control module.

• If less than 10 ohms

3. Ignition ON.

4. Test for greater than 10 V between the signal circuit terminal 7 and ground.

• If less than 10 V

1. Ignition OFF, disconnect the harness connector at the K9 body control module.

2. Test for infinite resistance between the signal circuit terminal 7 and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance

3. Test for less than 2 ohms in the signal circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the K9 body control module.

• If geater than 10 V

5. Test or replace the S78 turn signal/multifunction switch.

Rear Washer Pump Circuit Test

1. Ignition OFF, disconnect the X2 harness connector at the X50A underhood fuse block.

2. Connect a test lamp between the control circuit terminal 4 and ground, ignition ON.

3. Verify the test lamp turns ON and OFF when commanding the Rear Washer Relay Command On and Off with a scan tool.

• If the test lamp is always OFF

1. Ignition OFF, disconnect the harness connector at the K9 body control module, ignition ON.

2. Test for infinite resistance between the control circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance

3. Test for less than 2 ohms in the control circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the K9 body control module.

• If the test lamp is always ON

1. Ignition OFF, disconnect the harness connector at the K9 body control module, ignition ON.

2. Test for less than 1 V between the control circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.

• If less than 1 V, replace the K9 body control module.

• If the test lamp turns ON and OFF

4. Ignition OFF and all vehicle systems OFF, connect the X2 harness connector at the X50A underhood fuse block. Disconnect the harness connector at the G19 rear window washer pump. It may take up to 2 minutes for all vehicle systems to power down.

5. Test for less than 10 ohms between the ground circuit terminal 2 and ground.

• If 10 ohms or greater

1. Ignition OFF.

2. Test for less than 2 ohms in the low reference circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, repair the open/high resistance in the ground connection.

• If less than 10 ohms

6. Connect a test lamp between the control circuit terminal 1 and ground.

7. Verify the test lamp turns ON and OFF when commanding the Rear Washer Relay Command On and Off with a scan tool.

• If the test lamp is always OFF and the circuit fuse is good

1. Ignition OFF, disconnect the X1 harness connector at the X50A underhood fuse block.

2. Test for less than 2 ohms in the control circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the X50A underhood fuse block.

• If the test lamp is always OFF and the circuit fuse is open

1. Ignition OFF.

2. Test for infinite resistance between the control circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance, test or replace the X50A underhood fuse block.

• If the test lamp is always ON

1. Ignition OFF, disconnect the X1 harness connector at the X50A underhood fuse block.

2. Test for less than 1 V between the control circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.

• If less than 1 V, replace the X50A underhood fuse block.

• If the test lamp turns ON and OFF

8. Test or replace the G19 rear window washer pump.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

* Relay Replacement (Within an Electrical Center) Relay Replacement (Within an Electrical Center)Relay Replacement (Attached to Wire Harness) Relay Replacement (Attached to Wire Harness)

* Windshield Washer Pump Replacement (Terrain) Windshield Washer Pump Replacement (Terrain)Windshield Washer Pump Replacement (Equinox) Windshield Washer Pump Replacement (Equinox)

* Windshield Wiper and Washer Switch Replacement Service and Repair

* Control Module References Control Module References for BCM replacement, programming and setup

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