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.
Switch-Rear Window Defogger: Operation
An amber indicator in the rear window defogger switch will illuminate when the rear window defogger switch is activated. When the switch is activated, the A/C-heater control requests the front control module (FCM) to operated the rear window defogger (EBL) relay via the controller area network (CAN) B bus. The EBL relay controls the current flow to the heating grid of the rear window and when equipped, the heated outside rear view mirrors.
The EBL system will be automatically turned off after an initial programmed time interval of about 15 minutes as long as the ignition switch is the Run position. After the initial time interval has expired, if the rear window defogger switch is turned on again during the same ignition cycle, the EBL system will automatically turn off after about 10 minutes. The EBL system will also turn off if the ignition switch is turned to any position other than Run or by manually pressing the rear window defogger switch a second time.
The rear window defogger switch and the rear window defogger LED indicator cannot be repaired and, if faulty or damaged, the A/C-heater control must be replaced (Refer to HEATING & AIR CONDITIONING/CONTROLS/CONTROL-A/C HEATER - REMOVAL) .
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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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