Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Circuit/System Testing
2009 GMC Canyon 4D Pickup, 2.9 9SECTION Circuit/System Testing
WARNING: This page is about a different car, the 2008 Isuzu i-370, 2008 Isuzu i-290, 2008 GMC Canyon, and 2008 Chevrolet Colorado. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect the harness connector at the headlamp switch.
- Ignition ON, headlamps ON, connect a test lamp between the indicator control circuit terminal 8 and ground. The test lamp should not be illuminated.
- If the test lamp is illuminated, test the indicator control circuit for a short to voltage. If the circuit tests normal replace the BCM.
- Command the front fog lamps ON with a scan tool. The test lamp should be illuminated.
- If the test lamp is not illuminated, test the indicator control circuit for an open/high resistance or short to ground. If the circuit tests normal replace the BCM.
- If all the circuits test normal replace the headlamp switch.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.