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HOMESERVICE MANUALSCHEVROLET2008CHEVY EXPRESS G2500, VAN CARGO, 6.6 6REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 359 (DOOR SYSTEM, MIRROR SYSTEM & WINDOW SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESDTC B3820: LEFT REAR WINDOW DOWN CONTROL CIRCUITTEST DESCRIPTION
2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6

Test Description

2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6SECTION Test Description
WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 2:  Listen for an audible click when the left rear power window relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
  2. 3:  Tests for voltage at the coil side of the left rear power window down relay.
  3. 4:  Verifies that the BCM is providing ground to the left rear power window down relay.
  4. 5:  Tests if ground is constantly being applied to the left rear power window down relay.
DTC B3820

Step Action Yes No
Schematic Reference:  Power Window Schematics  
Connector End View Reference: Power Door Systems Connector End Views  
1 Did you perform the Door Systems Diagnostic System Check? Go to Step 2  Go to Diagnostic System Check - Door Systems 
2 
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, command the left rear power window down relay ON and OFF.
Does the left rear power window up relay turn ON and OFF with each command?		 Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems Go to Step 3 
3 
  1. Turn OFF the ignition.
  2. Disconnect the left rear power window switch.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the battery positive voltage circuit of the left rear power window switch with a test lamp that is connected to a good ground.
Does the test lamp illuminate?		 Go to Step 4  Go to Step 10 
4 
  1. Connect a test lamp between the control circuit of the left rear power window down relay and the battery positive voltage circuit of the left rear power window switch.
  2. With a scan tool, command the left rear power window down relay ON and OFF.
Does the test lamp turn ON and OFF with each command?		 Go to Step 8  Go to Step 5 
5  Does the test lamp remain illuminated with each command? Go to Step 7  Go to Step 6 
6 Test the control circuit of the left rear power window down relay for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 13  Go to Step 9 
7 Test the control circuit of the left rear power window down relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 13  Go to Step 9 
8 Inspect for poor connections at the left rear power window switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 13  Go to Step 11 
9 Inspect for poor connections at the harness connector of the Body Control Module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 13  Go to Step 12 
10 Repair the open or short to ground in the battery positive voltage circuit of the left rear power window switch. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 Go to Step 13  -
11 Replace the left rear power window switch.
Did you complete the replacement?		 Go to Step 13  -
12
IMPORTANT: Perform the set up procedure for the Body Control Module.
Replace the Body Control Module. Refer to Body Control Module Replacement in Body Control System.Did you complete the replacement?		 Go to Step 13  -
13
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset?		 Go to Step 2  System OK
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.