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.
Rear Window Defrost
The heating ventilation air conditioning (HVAC) module controls the rear window defrost grid and heated mirrors (if equipped) by controlling the state of the rear window defrost relay. When the rear window defrost switch (integral to the HVAC module) is pressed, the HVAC module will activate the rear window defrost relay. When the relay is active, both the rear window defrost grid and the heated exterior rear view mirror glass elements are energized.
The HVAC module will deactivate the rear window defrost relay when one of the following conditions is met:
- The rear window defrost switch is pressed when the feature is active
- The ignition switch state is changed from ON to OFF/LOCK
- The 15-minute timing function is complete
NO RELATED
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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.