B3875

DTC B3875

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



DTC Descriptor
DTC B3875 00
- Wiper High Speed Relay Circuit




Diagnostic Fault Information






Circuit/System Description

The body control module (BCM) controls the wiper motor based on input from the windshield wiper washer switch. The BCM monitors the wiper washer switch through three 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

A high speed wiper request is present.


Conditions for Setting the DTC

A short to voltage is detected in the windshield wiper high speed relay control circuit.


Action Taken When the DTC Sets

High speed wiper operation is suspended.


Conditions for Clearing the DTC

* A current DTC will clear when the condition for setting the fault is no longer seen.
* A history DTC will clear after 50 consecutive ignition cycles without a fault present.



Reference Information
Schematic Reference

Wiper/Washer Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Wiper/Washer System Description and Operation (Wiper/Washer System Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


Circuit/System Verification

Ignition ON, wiper switch in the HIGH position. Verify the windshield wipers are cycling at the high speed.


Circuit/System Testing

1. Ignition OFF, disconnect the WPR HI relay.
2. Connect a test lamp between the control circuit terminal C14 and B+.
3. Ignition ON, command the high speed wipers ON and OFF using the wiper 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 ground. If the circuit tests normal, replace the BCM.
• If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

4. If all circuits test normal, test or replace the WPR HI relay.



Component Testing


Relay Test
1. Ignition OFF, disconnect the WPR HI relay.
2. Test for 60-200 ohms between terminals A15 and C14.

• If the resistance is not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

* C15 and C14
* C15 and A14
* C15 and A15
* A15 and A14


• If not the specified value, replace the relay.

4. Test for less than 2 ohms between terminals E15 and B14.

• If greater than the specified range, replace the relay.

5. Install a 10A fused jumper wire between relay terminal A15 and 12 volts. Install a jumper wire between relay terminal C14 and ground. Test for less than 2 ohms between terminals C15 and A14.

• If greater than the specified range, replace the relay.




Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.


Control Module References (Programming and Relearning) for BCM replacement, setup, and programming