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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1746 (LIGHTING SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESDTC B2533TEST DESCRIPTION
2003 Chevrolet TrailBlazer 4.2 S, 4WD

Test Description

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Test Description
WARNING: This page is about a different car, the 2007 Saturn Vue. 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 fog lamp relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
  2. 3:  This step tests for voltage at the coil side of the fog lamp relay.
  3. 4:  This step verifies that the BCM is providing ground to the fog lamp relay.
DTC B2533

Step Action Yes No
Schematic Reference: Fog Lights Schematics 
1 Did you perform the Diagnostic System Check - Vehicle? Go to Step 2  Go to Diagnostic System Check - Vehicle
2 
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, command the fog lamp relay ON and OFF.
Does the fog lamp relay state change with each command?		 Go to Testing for Intermittent Conditions and Poor Connections Go to Step 3 
3 
  1. Turn OFF the ignition.
  2. Disconnect the fog lamp relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Turn the headlamp switch to the PARK or HEAD position.
  5. Probe the coil side battery positive voltage circuit between the fog lamp relay and the headlamp switch with a test lamp that is connected to a good ground.
Does the test lamp illuminate?		 Go to Step 4  Go to Step 8 
4 
  1. Connect a test lamp between the control circuit of the fog lamp relay and the coil side battery positive voltage circuit of the fog lamp relay.
  2. Place the headlamp switch in the PARK or HEADLAMP position.
  3. With a scan tool, command the fog lamp relay ON and OFF.
Does the test lamp turn ON and OFF with each command?		 Go to Step 6  Go to Step 5 
5 Test the control circuit of the fog lamp relay for a short to voltage. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?		 Go to Step 11  Go to Step 7 
6 Inspect for poor connections at the fog lamp relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 Go to Step 11  Go to Step 9 
7 Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?		 Go to Step 11  Go to Step 10 
8 Repair the open in the coil side battery positive voltage circuit of the fog lamp relay. Refer to Wiring Repairs .
Did you complete the repair?		 Go to Step 11  -
9 Replace the fog lamp relay.
Did you complete the replacement?		 Go to Step 11  -
10 Replace the BCM. Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?		 Go to Step 11  -
11
  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.