Circuit/System Testing

2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6SECTION Circuit/System Testing
WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the X7 harness connector at the appropriate door module.
  2. Ignition ON, verify a test lamp does not illuminate between the following circuit terminals and ground:
    • Control circuit terminal 1
    • Control circuit terminal 2
    • If the test lamp illuminates, test the appropriate circuit for a short to voltage.
  3. Ignition OFF, test for infinite resistance between the following circuits and ground:
    • Control circuit terminal 1
    • Control circuit terminal 2
    • If less than the specified value, test the appropriate circuit for a short to ground. If the circuits test normal, test or replace the rearview mirror.
  4. Test for 5-15 ohms between the control circuit terminal 1 and the control circuit terminal 2.
    • If not within the specified range, test both control circuits for an open/high resistance. If the circuits test normal, test or replace the rearview mirror.
  5. If all circuits test normal, replace the appropriate door module.
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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.