Rear Washer System Malfunction

Rear Washer System Malfunction

Diagnostic Instructions

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

Connector End View Reference

Component Connector End Views

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

1. Ignition ON, observe the scan tool Rear Window Washer Switch parameter while activating the S82 Windscreen Wiper/Washer Switch. The parameter should change between Active and Inactive.

⇒	If the value does not change, refer to Multifunction Switch Malfunction.

2. Operate the rear window washer using the S82 Windscreen Wiper/Washer Switch. Verify that the G24 Windscreen Washer Pump activates. Verify the washer fluid reservoir is filled up.

⇒	If the G24 Windshield Washer Pump does not run, refer to Washer Pump Malfunction.

⇒	If the G24 Windscreen Washer Pump does not shut off, test or replace the KR6 Rear Window Washer Pump Relay.

Circuit/System Testing

Note:  You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

Multifunction Switch Malfunction

1. Ignition OFF, disconnect the X2 and the X3 harness connector at the K9 Body Control Module.
2. Test for 5.90-6.30 kΩ between ground circuit terminal 10 X3 and signal circuit terminal 12 X2 while activating the rear wash switch.

⇒	If less than the specified value, test the circuits for a short to ground.

⇒	If greater than the specified value, test the reference circuit for an open/high resistance and a short to voltage.

3. If the circuits tests normal, test or replace the S82 Windscreen Wiper/Washer Switch.
4. If all circuits test normal, test or replace the K9 Body Control Module.

Washer Pump Malfunction

1. Ignition OFF, disconnect the harness connector at the G24 Windscreen Washer Pump.
2. Test for less than 5 Ω between ground and the ground circuits listed below:

•	Terminal 1

•	Terminal 2

⇒	If greater than the specified value, test the ground circuits for an open/high resistance or a short to voltage.

3. Install a test lamp between the ground circuit terminal 2 and the control circuit terminal 1.
4. Ignition ON, command the Rear Washer Relay Command On and OFF with a scan tool. The test lamp should turn ON and OFF as commanded.
5. If the test lamp does not illuminate as expected, test the control circuit for an open/high resistance or a short to ground.
6. If all circuits test normal, test or replace the G24 Windscreen Washer Pump.

Component Testing

Output Control Tests

1. Ignition ON, command the Rear Washer Relay Command ON and OFF with a scan tool. Observe that the KR6 Rear Window Washer Pump Relay clicks and the G24 Windshield Washer Pump runs.

⇒	If the KR6 Rear Window Washer Pump Relay does not work, test or replace the X50A Fuse Block - Underbonnet.

⇒	If the KR6 Rear Window Washer Pump Relay does work, but the G24 Windshield Washer Pump does not run, test the G24 Windshield Washer Pump ground and control circuit.

⇒	If all circuits test normal, replace the G24 Windscreen Washer Pump.

Multifunction Switch - Static Test

1. Ignition OFF, remove the S82 Windscreen Wiper/Washer Switch.
2. Test for 5.90-6.30 kΩ between signal terminal 2 and 4 at the S82 Windscreen Wiper/Washer Switch while activating the rear wash switch.

⇒	If the resistance is not within the specified range, replace the S82 Windscreen Wiper/Washer Switch.

Washer Pump - Dynamic Test

1. Ignition OFF, disconnect the harness connector at the G24 Windscreen Washer Pump.
2. Install a 10A fused jumper wire between the control terminal 1 and 12V. Install a jumper wire between the ground terminal 2 and ground.
3. Verify the G24 Windscreen Washer Pump is activated.

⇒	If the G24 Windscreen Washer Pump does not activate, replace the G24 Windscreen Washer Pump.

Relay Test

1. Ignition OFF, Retained Accessory Power OFF, disconnect the harness connector X5 at the K9 Body Control Module.
2. Test for 120-160 Ω between control terminal 9 and ground.

⇒	If less than the specified value, test the control circuit for a short to ground.

⇒	If greater than the specified value, test the control circuit for an open/high resistance or a short to voltage.

3. If all circuits test normal, test or replace the K9 Body Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.