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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 571 (Lighting Systems) >> Diagnostic Information and Procedures >> DTC B2578: Short To Battery In Headlamp Relay Control Circuit >> Test Description

Test Description

WARNING: This page is about a different car, the 2002 Buick Regal and 2002 Buick Century. 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 headlamp relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
  2. 3.  Verifies that the BCM is providing ground to the headlamp lamp relay. Indicating a short to voltage internal to the headlamp lamp relay.
  3. 4.  Test for a short to voltage in the control circuit of the headlamp relay.
  4. Fig 1: Identifying DTC B2578 Diagnostic Table
    G01754789Courtesy of GENERAL MOTORS CORP.