B3875
DTC B3875 (V6) (3.8L)
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 and monitors the state of the wiper high speed relay control circuit. When the windshield wiper switch is placed in to a high speed setting, a signal is applied to the BCM through the windshield wiper switch high signal circuit. The BCM then applies battery positive voltage to the Wiper HI relay through the wiper High speed relay control circuit. This energizes the Wiper HI relay, allowing battery positive voltage to be applies from the wiper/ws fuse, through the switched contacts of the wiper relay and through the switched contracts of the Wiper HI relay to the windshield wiper motor. Ground is applied at all times to the coil side of the wiper HI relay and to the windshield wiper motor from G201.
Conditions for Running the DTC
* The ignition is in the ON position.
* The ignition voltage is between 9-16 volts.
Conditions for Setting the DTC
* The BCM detects an short to battery positive voltage in the wiper high speed relay control circuit for over 1 second.
* The BCM detects an open or a short to ground in the wiper high speed relay control circuit for over 1 second.
Action Taken When the DTC Sets
The BCM will not activate the output.
Conditions for Clearing the DTC
* The current DTC will become history when the request for the output is removed or when the condition for setting the fault is corrected.
* The 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 (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 Wiper HI Relay.
2. Connect a test lamp between the control circuit terminal C14 and ground.
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 Voltage. If the circuit tests normal, replace the BCM.
• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
4. If all circuits test normal, test or replace the WIPER HI Relay.
Component Testing
Relay Test
1. Ignition OFF, disconnect the WIPER HI relay.
2. Test for 60-200 ohms between terminals C14 and A15.
• If the resistance is not within the specified range, replace the relay.
3. Test for infinite resistance between the following terminals:
* C15 and A15
* C15 and A14
* C15 and C14
* C14 and A14
• If not the specified value, replace the relay.
4. Test for less than 2 ohms between terminals C15 and B14.
• If greater than the specified range, replace the relay.
5. Install a 10A fused jumper wire between relay terminal C14 and 12 volts. Install a jumper wire between relay terminal A15 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.
* Underhood Electrical Center or Junction Block Replacement (Underhood Electrical Center or Junction Block Replacement)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming