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.
2008 Chevrolet TrailBlazer 6.0 H, AWDFACTORY OEM SERVICE PROCEDURE
Circuit/System Testing
- Ignition OFF, disable the SIR system. Refer to SIR Disabling and Enabling .
- Disconnect the turn signal multifunction switch harness connector X4.
- Ignition ON, verify that the scan tool Cruise Resume/Accel. Switch parameter displays Off or Inactive.
- If the scan tool parameter reads On, Active or Invalid, test the cruise control resume/accel switch signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
- Connect a 3 amp fused jumper between terminals A and C of the turn signal multifunction switch harness connector X4. Verify that the scan tool Cruise Resume/Accel. Switch parameter displays On.
- If the scan tool parameter reads Off test the cruise control resume/accel. switch signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
- If the circuit tests normal, test or replace the cruise control switch assembly.
Factory Service Tools
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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.
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