Circuit/System Testing

2009 Chevrolet Tahoe Base, 4.8 CSECTION Circuit/System Testing
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the X5 harness connector at the BCM.
  2. Ignition ON, verify that the low speed wipers are not on.
    • If the low speed wipers are on, test the WIPER 1 relay control circuit terminal 20 for a short to voltage. If the circuit tests normal, replace the underhood fuse block.
  3. Install a 10A fused jumper wire between the WIPER 1 relay control circuit terminal 20 and B+. Verify the low speed wipers are on.
    • If the low speed wipers are not on, test the relay control circuit for an open/high resistance or short to ground. If the circuit tests normal replace the underhood fuse block.
  4. If all circuits test normal, replace the BCM.
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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.