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.
Diagnostic Fault Information
Circuit/System Description
The rear window washer pump is controlled by the rear window wiper washer switch through the rear washer pump relay. The switch supply voltage is from the body control module (BCM), and when the WASH switch is pressed battery voltage is applied to the rear washer relay control circuit and to the rear wiper switch signal circuit. When the rear wiper motor module receives battery voltage on the rear wiper switch signal circuit, the wiper motor will operate continuously for as long as the voltage is present and several cycles after the switch is released. The rear washer relay control circuit is used to energize the relay coil and close the rear washer pump control circuit to battery voltage.
Circuit/System Verification
1. Ignition ON, verify the rear wiper operates normally using the rear wiper switch.
^ If the rear wiper does not operate properly, refer to Rear Wiper System Malfunction. Rear Wiper System Malfunction
2. Connect a test lamp between the relay side of the REAR WASH fuse and ground.
3. Verify that the test lamp turns on and off while pressing and releasing the rear window washer switch.
^ If the test lamp does not turn on and off while changing between the commanded states, refer to the Rear Washer Pump Relay Control Circuit Test.
4. If the rear washer pump does not operate properly, refer to the Rear Washer Pump Circuit Test.
Circuit/System Testing
Rear Washer Pump Relay Control Circuit Test
1. Disconnect the X4 harness connector at the turn signal/multifunction switch.
2. Ignition ON, verify the rear washer pump is not on.
^ If the rear washer pump is on, test the rear washer pump relay control circuit for a short to voltage. If the circuit tests normal, refer to the Rear Washer Pump Circuit Test.
3. Install a 15A fused jumper wire between the relay control circuit terminal 3 and ground. Verify the rear washer pump is on.
^ If the rear washer pump is not on, test the rear washer pump relay control circuit for an open/high resistance or short to ground. If the circuit tests normal replace the underhood fuse block.
4. If all circuits test normal, test or replace the turn signal/multifunction switch.
Rear Washer Pump Circuit Test
1. Ignition OFF, disconnect the harness connector at the rear washer pump.
2. Test for less than 1.0 ohm of resistance between the ground circuit terminal B and ground.
^ If greater than the specified range, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the control circuit terminal A and the ground circuit terminal B.
4. Press and release the rear window 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, replace the 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 underhood fuse block.
5. If all circuits test normal, test or replace the rear washer pump.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Rear Window Wiper and Washer Switch Replacement
* Rear Window Washer Pump Replacement
* Rear Window Wiper Motor Replacement
* Underhood Electrical Center or Junction Block Replacement