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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1085 (Lighting Systems) >> Diagnostic Information and Procedures >> DTC B3857: Headlamp High Beam Signal Circuit >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. 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:  Test for a short to battery positive voltage in the high beam headlamp signal circuit.
  2. 3:  Test for a short to ground or an open in the high beam headlamp signal circuit.
DTC B3857

Step Action Yes No
Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics 
Connector End View Reference: Master Electrical Component List in Wiring Systems.
1 Did you perform the Lighting System Diagnostic System Check? Go to Step 2  Go to Diagnostic System Check - Lighting Systems 
2 
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Turn the headlamp switch OFF.
  4. With a scan tool, observe the high beam input data.
Does the scan tool display 0 Volts?		 Go to Step 3  Go to Step 4 
3 
  1. Turn the high beam headlamps ON.
  2. With the scan tool, observe the high beam input data.
Does the high beam input parameter change state?		 Go to Diagnostic Aids Go to Step 5 
4 Test the high beam circuit for a short to battery positive voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 7  Go to Step 5 
5 Inspect for a high resistance or a short to ground in the high beam headlamp sensing circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 7  Go to Step 6 
6
IMPORTANT: Perform the set up procedure for the body control module. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control Systems.
Replace the body control module. Refer to Body Control Module Replacement in Body Control Systems.Did you complete the replacement?		 Go to Step 7  -
7
  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
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