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.
Scan Tool Data Definitions
- Rear Defog Relay Cmd.
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The scan tool displays On/Off. The body control module will indicate if it is commanding the rear defog relay On or Off.
- Rear Defog Relay Fdbk.
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The scan tool displays High/Low. This input to the BCM displays the state of the rear defog relay feedback circuit. Low is displayed when the BCM is providing a ground to the rear defog relay control circuit.
- Rear Defog Switch
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The scan tool displays On/Off. The BCM receives an input from the HVAC control head indicating On when the rear defog system is turned On.
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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.