B3875
DTC B3715 or B3875
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.
DTC Descriptors
DTC B3715 02
-
Windshield Wiper Relay Circuit Short to Ground
DTC B3875 01
-
Windshield Wiper High Speed Relay Circuit Short to Battery
DTC B3875 02
-
Windshield Wiper High Speed Relay Circuit Short to Ground
DTC B3875 04
-
Windshield Wiper High Speed Relay Circuit Open
Diagnostic Fault Information
Circuit/System Description
The body control module (BCM) controls the windshield wiper motor based on input from the windshield wiper/washer switch. The BCM monitors the wiper/washer switch through two separate signal circuits and a ground circuit. The windshield wiper switch high signal circuit is used to determine high speed wiper operation, the windshield wiper switch low signal is used to determine low speed, intermittent, and mist operation through the use of a resistor ladder, and windshield washer switch signal circuit is used to determine washer operation.
The BCM controls the windshield wiper motor through two output controls, controlling two relays which determine the desired wiper speed, high or low.
Conditions for Running the DTC
* The DTC runs only when a wiper output is actively being requested by the BCM.
* The system voltage is between 9-16 V.
Conditions for Setting the DTC
* A short to ground is detected in the Front Wiper Relay control circuit or in the High Speed Relay control circuit.
* A short to voltage or an open/high resistance is detected in the High Speed Relay control circuit.
Action Taken When the DTC Sets
The BCM will not activate the wiper output.
Conditions for Clearing the DTC
* A current DTC will clear when the condition for setting the fault is no longer present.
* A history DTC will clear after 50 consecutive ignition cycles without a fault present.
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 Testing
DTC B3715
1. Ignition OFF and all vehicle systems OFF, disconnect the KR12B windshield wiper relay. 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 85 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. Connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85, ignition ON.
4. Verify the test lamp turns ON and OFF when commanding the wipers ON and OFF with a scan tool.
• If the test lamp is always OFF
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 the test lamp is always ON
1. Ignition OFF, disconnect the harness connector at the K9 body control module, ignition ON.
2. 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 K9 body control module.
• If the test lamp turns ON and OFF
5. Test or replace the KR12B windshield wiper relay.
DTC B3875
1. Ignition OFF, disconnect the KR12C windshield wiper speed control relay, ignition ON.
2. Verify a test lamp illuminates between the B+ circuit terminal 85 and ground.
• If the test lamp does not illuminate and the circuit fuse is good
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 the test lamp does not illuminate and the circuit fuse is open
1. Ignition OFF.
2. Test for infinite resistance between the B+ circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, test or replace the KR12C windshield wiper speed control relay.
• If the test lamp illuminates
3. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86, ignition ON.
4. Verify the test lamp turns ON and OFF when commanding the wipers ON and OFF with a scan tool.
• If the test lamp is always OFF
1. Ignition OFF, disconnect the harness connector at the K9 body control module, ignition ON.
2. 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
3. Ignition OFF.
4. 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 the test lamp is always ON
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, replace the K9 body control module.
• If the test lamp turns ON and OFF
5. Test or replace the KR12C windshield wiper speed control relay.
Component Testing
Relay Test
1. Ignition OFF, disconnect the appropriate relay.
2. Test for 60-200 ohms between terminals 85 and 86.
• If less than 60 or greater than 200
Replace the relay.
• If between 60-200 ohms
3. Test for infinite resistance between the terminals listed below:
* 30 and 86
* 30 and 87
* 30 and 85
* 85 and 87
• If less than infinite resistance
Replace the relay.
• If infinite resistance
4. Test for less than 5 ohms between terminals 30 and 87A.
• If 5 ohms or greater
Replace the relay.
• If less than 5 ohms
5. Install a 10 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground.
6. Test for less than 5 ohms between terminals 30 and 87.
• If 5 ohms or greater
Replace the relay.
• If less than 5 ohms
7. All OK
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Relay Replacement (Within an Electrical Center) Relay Replacement (Within an Electrical Center)Relay Replacement (Attached to Wire Harness) Relay Replacement (Attached to Wire Harness)
* Control Module References Control Module References for BCM replacement, programming and setup