Test Description

1999 GMC Forward Control 5.7 R, AutomaticSECTION 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.Β  This step will test the if the sunroof will slide to the open position. If it opens, then inspect the limit switch LS2 for a stuck switch causing an intermittent short to ground.
  2. 4.Β  Testing for a short to ground in the LS2 limit switch circuit or a stuck limit switch (closed).
  3. Fig 1: Identifying Power Sunroof Does Not Open Diagnostic Table
    G01755966Courtesy of GENERAL MOTORS CORP.
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:

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