B3821

DTC B3821 or B3824

Diagnostic Instructions

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

DTC Descriptors

DTC B3821
- Left Rear Window Relay Power Circuit

DTC B3824
- Right Rear Window Relay Power Circuit

Diagnostic Fault Information






Circuit/System Description

The body control module (BCM) supplies voltage to the rear window switches allowing for normal window operation from the rear switches and the driver master control. If the rear window lockout function is enabled, the BCM will not supply voltage to the rear window switches and the rear windows will 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.

Conditions for Setting the DTC

B3821

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

B3824

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.

Circuit/System Verification

1. 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 command.
2. Observe the scan tool Window Lockout parameter while pressing and depressing the window lockout switch on the driver master control. The reading should change between ON and OFF.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the appropriate rear window switch.
2. Ignition ON, test for more than 10 volts between the power window lockout rear control circuit terminal D and ground with the rear windows enabled from the driver master control.

^ 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.

3. Test for 0 volts between the power window lockout rear control circuit terminal D and ground with the rear windows disabled from the driver master control.

^ If greater than the specified value, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.

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

Repair Instructions

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

* Rear Side Door Window Switch Replacement