B3821

DTC B3821 or B3824

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 B3821 00
- Left Rear Window Relay Power Circuit

DTC B3824 00
- Right Rear Window Relay Power Circuit

Diagnostic Fault Information





Circuit/System Description

The body control module (BCM) monitors the window lockout command from the driver door switch (DDS). When the rear window switch operation is authorized, the the BCM signal voltage drops approximately 5 volts to the rear window switches allowing for normal window operation from the rear switches. If the rear window lockout function is commanded, the BCM signal voltage is at B+ voltage which disables the rear window switches and the rear windows will only operate when the BCM receives a command from the driver master control.

Conditions for Running the DTC

* Battery voltage is between 9-16 volts.
* The ignition is ON.

Conditions for Setting the DTC

B3821 00

The BCM detects a fault in the left rear window lockout circuit.

B3824 00

The BCM detects a fault in the right rear window lockout circuit.

Action Taken When the DTC Sets

The left or right rear power window will be inoperative.

Conditions for Clearing the DTC

* The DTC will be current for as long as the fault is present.
* When the fault is no longer present, the DTC will be a history DTC.
* A history DTC will clear after 50 ignition cycles

Reference Information
Schematic Reference

Moveable Window Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Power Windows Description and Operation (Power Windows)
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 (Programming and Relearning) for scan tool information

Circuit/System Verification

Ignition ON, command the rear windows UP and DOWN by using the window switches on the driver master control and their respective rear window switches. The rear windows should perform the UP and DOWN function from each switch.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the appropriate rear window switch.
2. Ignition ON, enable the rear window switches by pressing the window lockout switch on the driver master control.
3. Test for greater than 9 volts between the control circuit terminal D and ground.

• If less than the specified range, test the control circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the BCM.

4. If all circuits test normal, replace the rear window switch.

Repair Instructions

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

* Rear Side Door Window Switch Replacement (Crew Cab) (Rear Side Door Window Switch Replacement (Crew Cab))Rear Side Door Window Switch Replacement (Extended Cab) (Rear Side Door Window Switch Replacement (Extended Cab))
* Control Module References (Programming and Relearning) for BCM replacement, setup and programming