Rear Wiper System Malfunction
Rear Wiper 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
The body control module (BCM) controls the single speed rear wiper motor by its active high output to the external rear wiper motor relay. When the BCM activates its output and applies battery to the coil of the relay, the relay energizes, allowing battery voltage from the fuse to be applied through the switched contacts of the rear wiper motor relay to the control input of the rear wiper motor. The motor then operates continuously at low speed.
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 Wiper/Washer System
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
1. Ignition ON.
2. S78 turn signal/multifunction switch in rear wiper ON position.
3. Verify rear wipers ON.
• If wipers not ON
1. Verify the scan tool Rear Wiper Switch parameter is Active when operating the rear wipers.
• If the parameter is not Active, refer to Rear Wiper/Washer Switch Circuit Test.
• If the parameter is Active, refer to Rear Wiper Relay Circuit Test.
• If wipers ON
4. Refer to Rear Wiper Motor Circuit Test.
Circuit/System Testing
Rear Wiper/Washer Switch Circuit Test
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the S78 turn signal/multifunction switch. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the low reference terminal 1 and ground.
• If 10 ohms or greater
1. Ignition OFF, disconnect the X2 harness connector at the body control module.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K9 body control module.
• If less than 10 ohms
3. Ignition ON.
4. Test for greater than 10 V between control circuit terminal 7 and ground.
• If 10 V or less
1. Ignition OFF, disconnect the harness connector at the K9 body control module.
2. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K9 body control module.
• If greater than 10 V
5. Test or replace the S78 turn signal/multifunction switch.
Rear Wiper Motor Circuit Test
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the M45 rear wiper motor. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the ground circuit terminal 1 and ground.
• If 10 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
3. Ignition ON.
4. Verify a test lamp illuminates between the B+ circuit terminal 3 and ground.
• If the test lamp does not illuminate and the circuit fuse is OK
1. Ignition OFF.
2. Test for less than 2 ohms in the B+ circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, verify the fuse is OK and there is voltage at the fuse. If there is voltage at the fuse, replace the X50A underhood fuse block.
• If the test lamp does not illuminate and the circuit fuse is open
1. Ignition OFF, test for infinite resistance between the B+ circuit terminal 3 and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
2. Test for infinite resistance between the control circuit terminal 2 and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the M45 rear wiper motor.
• If the test lamp illuminates
5. Connect a test lamp between the control circuit terminal 2 and the ground circuit terminal 1.
6. Verify the test lamp turns ON and OFF when commanding the rear wipers ON and OFF using the S78 turn signal/multifunction switch.
• If the test lamp is always OFF
1. Ignition OFF, test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
2. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the X50A underhood fuse block.
• If the test lamp is always ON
Ignition OFF, test for less than 1 V between the control circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the X50A underhood fuse block.
• If the test lamp turns ON and OFF
7. Test or replace the M45 rear wiper motor.
Rear Wiper Relay Circuit Test
1. Ignition OFF and all vehicle systems OFF. Disconnect the X2 harness connector at the X50A Fuse Block. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the ground circuit terminal 39 and ground.
• If greater than 10 ohms
1. Test for less than 2 ohms in the ground circuit end to end.
• If greater than 2 ohms, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
3. Connect a test lamp between the control circuit terminal 27 and ground circuit terminal 39, ignition ON.
4. Verify the test lamp turns ON and OFF when commanding the Rear Wiper Switch ON and OFF with a scan tool.
• If the test lamp always OFF
1. Ignition OFF, disconnect the X4 harness connector at the body control module.
2. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground in the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the control circuit end to end.
• If greater than 2 ohms, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K9 body control module.
• If the test lamp always ON
1. Ignition OFF, disconnect the X4 harness connector at the body control module, ignition ON.
2. Test for less than 1 V between the control circuit and ground.
• If greater than 1 V, repair the short to voltage in the circuit.
• If less than 1 V, replace the K9 body control module.
• If test lamp turns ON and OFF
5. Test or replace the X50 Fuse Block.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Rear Window Wiper Motor Replacement (Hatchback) Rear Window Wiper Motor Replacement (Hatchback)
* Windshield Wiper and Washer Switch Replacement Service and Repair
* Control Module References Control Module References or BCM replacement, programming and setup