B3821

DTC B3821 or B3824

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* ReviewStrategy 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 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 rear window switches continuously monitor the enable/disable signal voltage sent by the body control module (BCM) and compares the signal voltage to the B+ voltage. If the rear window lockout function is enabled, the signal is at or near B+ voltage allowing for normal rear window switch function and when disabled, the signal voltage drops by approximately 0.5 volts and the rear window switches will disable the rear window switch function. The rear windows will then only operate when the BCM receives a command to operate the appropriate rear window UP or DOWN from the driver door module (DDM).

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 from the door switch and the driver master control.

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 ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Power Windows Description and Operation (Power Windows 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, command the rear passenger power windows UP and DOWN with a scan tool, the rear passenger power windows should perform the UP and DOWN function.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the appropriate rear window switch.
2. Ignition ON, verify the scan tool LR Window Enable Cmd. and RR Window Enable Cmd. parameters are On.

• If not the specified value, press 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 (Rear Side Door Window Switch Replacement)
* Control Module References (Programming and Relearning) for BCM replacement, setup and programming