Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | 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 | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Rear Window Wiper Motor B+ | 1 | 1 | -- | -- |
Rear Window Wiper Switch Supply | 1 | 1 | 4 | -- |
Rear Window Wiper Switch Signal | 1 | 1 | 2 | -- |
Liftgate Ajar Switch Signal | 1 | 3 | 3 | -- |
Rear Window Wiper Motor Ground | -- | 1 | -- | -- |
1. Rear Window Wiper Motor Inoperative 2. Rear Window Wiper Motor Always On 3. Rear Window Wiper Motor Operates with Liftgate or Liftgate Window Open 4. Rear Window Wiper Motor Operates with Ignition Off | ||||
Circuit/System Description
The rear wiper is controlled based on an input from the rear wiper/washer switch. When the switch is in the ON or DELAY, a voltage signal is sent to the rear window wiper motor indicating the desired speed. Each switch position has resistor that drops the voltage to a specified value which is interpreted by the rear window wiper motor as ON or DELAY. The rear wiper motor receives B+ voltage from the I/P fuse block and accessory voltage from the BCM.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Rear Wiper/Washer System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Ignition ON, observe the scan tool BCM Rear Closure Ajar Sw. parameter while opening and closing the liftgate. The reading should change between Active and Inactive.
- Press and release the rear window washer switch. The rear window wiper motor and pump will operate continuously for as long as the wash switch is pressed and several wipe cycles will occur after the switch is released.
- Operate the rear window wiper switch to DELAY, ON, and OFF. The rear window wiper motor will operate in a delayed wipe cycle mode then a continuous wipe cycle mode and stop in the park position.
| ⇒ | If not the specified value, refer to Liftgate Ajar Indicator Malfunction . |
| ⇒ | If the rear wiper motor and the rear washer pump are inoperative, refer to Rear Wiper Washer Switch Circuit Test. |
| ⇒ | If the rear washer pump operates normal and the rear wiper motor is inoperative, refer to the Rear Wiper Motor Circuit Test. |
| ⇒ | If the wiper motor is inoperative in the DELAY or ON modes, refer to the Rear Wiper Motor Circuit Test. |
| ⇒ | If the rear wiper stops out of the park position, replace the rear window wiper motor. |
Circuit/System Testing
Rear Wiper Washer Switch Circuit Test
- Ignition OFF, disconnect the harness connector at the rear wiper switch.
- Ignition On, verify that a test lamp illuminates between the ignition supply circuit terminal 5 and ground.
- Install a 3A fused jumper wire between the signal circuit terminal 3 and the ignition circuit terminal 5. Verify the rear wiper and washer are on.
- If all circuits test normal replace the turn signal multifunction switch.
| ⇒ | If the test lamp does not illuminate, test the switch supply circuit for a short to ground or an open/high resistance. If the circuit tests normal, refer to Power Mode Mismatch . |
| ⇒ | If the rear wiper and washer do not operate, test the switch signal circuit for an open/high resistance or short to ground. If the circuit tests normal replace the rear wiper motor. |
Rear Wiper Motor Control Circuit Test
- Ignition OFF, disconnect the harness connector at the rear window wiper motor.
- Test for less than 1.0 ohm between the ground circuit terminal B and ground.
- Verify that a test lamp illuminates between the B+ circuit terminal A and ground.
- Ignition ON, test for B+ at the switch signal circuit terminal E while the rear window wiper switch is in the delay and on switch positions.
- If all circuits test normal replace the rear window wiper motor.
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | If the test lamp does not illuminate, test the B+ circuit for an open/high resistance or short to ground. |
| ⇒ | If B+ is not present, test the switch signal circuit for an open/high resistance or short to ground. If the circuit tests normal replace the rear wiper switch. |
Component Testing
Rear Window Wiper Switch
- Ignition OFF, disconnect the harness connector at the rear wiper switch.
- Rear wiper switch OFF, test for infinite resistance between the ignition terminal 5 and the signal terminal 3.
- Rear wiper switch in the ON position, test for 2.5-3.5k ohms between the ignition terminal 5 and the signal terminal 3.
- With the rear wiper switch in the DELAY position, test for 900-1.5k ohms between the ignition terminal 5 and the signal terminal 3.
| ⇒ | If not the specified value, replace the rear wiper switch. |
| ⇒ | If not within the specified range, replace the turn signal multifunction switch. |
| ⇒ | If not within the specified range, replace the turn signal multifunction switch. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
