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 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 Fuel Pump and Level Sensor Assembly
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
Command the Rear Washer Relay Command ON and OFF with a scan tool. The rear washer should turn ON and OFF when changing between the commanded states.
If the rear washer does not turn ON and OFF, refer to the Washer Pump Circuit Test.
If the rear washer turns ON and OFF, refer to Rear Washer Switch Circuit Test.
Circuit/System Testing
Rear Washer Switch Circuit Test
1. Ignition OFF, disconnect the X1 harness connector at the S82 windshield wiper/washer switch.
2. Test for less than 5 ohms between the low reference terminal 2 and ground.
• If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K9 BCM.
3. Ignition ON, verify the rear washer is OFF.
• If not the specified value, test the signal circuit terminal 4 for a short to ground. If the circuit tests normal, replace the K9 BCM.
4. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the ground circuit terminal 2. Verify the rear washer turns ON.
• If the rear washer does not turn on, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
5. If all circuits test normal, test or replace the S82 windshield wiper/washer switch.
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 G2 and ground.
3. Command the Rear Washer Relay Command ON and OFF with a scan tool. 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, replace the K9 BCM.
• 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, replace the K9 BCM.
4. Ignition OFF, connect the X2 harness connector at the X50A underhood fuse block and disconnect the harness connector at the G24 windshield washer pump.
5. Connect a test lamp between control circuit terminal 1 and ground.
6. Ignition ON, command the Windshield Washer Relay Command ON and OFF with a scan tool. 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, replace the X50A underhood fuse block.
• 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, replace the X50A underhood fuse block.
7. Connect a test lamp between control circuit terminal 2 and ground.
8. Command the Rear Washer Relay Command ON and OFF with a scan tool. 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, replace the X50A underhood fuse block.
• 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, replace the X50A underhood fuse block.
9. If all circuits test normal, test or replace the G24 windshield washer pump.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Windshield Washer Pump Replacement Service and Repair
* Windshield Wiper and Washer Switch Replacement Service and Repair
* Control Module References Control Module References for BCM replacement, programming and setup