Rear Wiper System Malfunction

Rear Wiper System Malfunction

Diagnostic Instructions
^ Perform the [Diagnostic System Check - Vehicle Diagnostic Information] prior to using this diagnostic procedure. Diagnostic System Check - Vehicle Diagnostic Information
^ Review [Strategy Based Diagnosis] for an overview of the diagnostic approach.Strategy Based Diagnosis
^ [Diagnostic Procedure Instructions - Vehicle Diagnostic Information] provides an overview of each diagnostic category.Diagnostic Procedure Instructions - Vehicle Diagnostic Information

Circuit/System Description
The rear wiper is controlled based on an input from the rear wiper/washer switch. When the wiper portion of the rear wiper/washer switch is closed, a ground signal is provided to the rear window wiper motor indicating rear wiper operation is request. The rear wiper motor receives B+ voltage from the I/P fuse block and accessory voltage from the BCM. The rear wiper motor also monitors the state of the liftgate ajar indicator and will suspend rear wiper operating when the liftgate is open.

Circuit/System Verification
1. Ignition ON, liftgate closed, verify the liftgate ajar indicator is not illuminated.
^ If the liftgate ajar indicator is illuminated, refer to [Liftgate Ajar Indicator Malfunction]

2. Command the rear wiper ON using the rear wiper/washer switch. The rear wiper should activate.

Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the rear wiper/washer switch.
2. Test for less than 5 ohms of resistance between the ground circuit terminal 1 and ground.
^ If greater than the specified range, test the ground circuit for an open/high resistance.

3. Reconnect the harness connector at the rear wiper/washer switch. Disconnect the harness connector at the rear window wiper motor.
4. Test for less than 20 ohms of resistance between the ground circuit terminal A and ground.
^ If greater than the specified range, test the ground circuit for an open/high resistance.

5. Ignition ON, verify a test lamp illuminates between the B+ circuit terminal C and ground.
^ If the test lamp does not illuminate, test he B+ circuit for an open/high resistance. If the RR WPR fuse is open, test the B+ circuit for a short to ground. If the circuit tests normal, test or replace the rear window wiper motor.

6. Verify a test lamp illuminates between the ignition circuit terminal D and ground.
^ If the test lamp does not illuminate, test he ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

7. Ignition OFF, liftgate closed, test for less than 20 ohms of resistance between the signal circuit terminal F and ground.
^ If greater than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, refer to [Liftgate Ajar Indicator Malfunction].

8. Rear wiper switch closed, test for less than 10 ohms of resistance between the signal circuit terminal B and ground.
^ If greater than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, test or replace the rear wiper/washer switch.

9. If all circuits test normal, test or replace the rear window wiper motor.

Component Testing

Rear Wiper/Washer Switch
1. With the rear wiper switch in the open position, test for infinite resistance between the ground terminal 1 and the signal terminal 2.
^ If not the specified value, replace the rear wiper/washer switch.

2. With the rear wiper switch in the closed position, test for less than 2 ohms of resistance between the ground terminal 1 and the signal terminal 2.
^ If not within the specified range, replace the rear wiper/washer switch.

Repair Instructions
Perform the [Diagnostic Repair Verification - Vehicle Diagnostic Information] after completing the diagnostic procedure. Diagnostic Repair Verification - Vehicle Diagnostic Information
[Liftgate Wiper Motor Replacement]