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 has overviews of all diagnostic categories.

DTC Descriptor

DTC B371A 39

Windshield Wiper Motor Internal Malfunction

Circuit/System Description

B+ voltage and ground are supplied to the windshield wiper motor. The body control module (BCM), monitors the wiper motor park switch position and wiper switch position. When the BCM senses the wiper switch in the OFF position and does not sense the wiper motor park switch signal, the BCM will set this DTC.

Conditions for Running the DTC

The module runs the program to detect an internal fault when power up is commanded. The only requirements are voltage and ground. This program runs even if the voltage is out of the valid operating range.

Conditions for Setting the DTC

The BCM receives an invalid signal from the windshield wiper motor.

Action Taken When the DTC Sets

The module refuses all additional inputs.

Conditions for Clearing the DTC

A current DTC clears when the diagnostic runs and passes.

Diagnostic Aids

Diagnose any communication DTCs (U-Codes) before attempting any diagnosis.

Reference Information

Schematic Reference

Wiper/Washer Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Wiper/Washer System Description and Operation

Electrical Information Reference

•	Circuit Testing

•	Connector Repairs

•	Testing for Intermittent Conditions and Poor Connections

•	Wiring Repairs

Scan Tool Reference

Control Module References for information on diagnostic tools

Circuit/System Testing

1.	Ignition OFF, disconnect the harness connector at the M75 Windshield Wiper Motor.

2.	Test for less than 5 Ω between the ground circuit terminal A and ground.

3.	If greater than the specified range, test the ground circuit for an open/high resistance.

4.	Ignition ON, verify the scan tool BCM Windshield Wiper Park Switch parameter is Inactive.

5.	If not Inactive, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the K9 Body Control Module.

6.	Install a 3 A fused jumper wire between the wiper motor park switch signal circuit terminal B and ground. Verify the scan tool Windshield Wiper Park Switch parameter is Active.

7.	If not Active, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module.

8.	If all circuits test normal, test or replace the M75 Windshield Wiper Motor

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Control Module References for information on BCM replacement, setup, and programming

•	Windshield Wiper Motor Replacement