Rear Defogger Switch - Operation

OPERATION

When the momentary push button switch for the rear window defogger system, also known as the Electric Back Light (EBL), is pressed to on, a request signal is sent to the Body Control Module (BCM) over hard-wired circuits to energize the EBL relay located in the Power Distribution Center (PDC). When the EBL relay is energized, fused battery current is directed to the rear window defogger grid lines. The grid lines heat the glass to help clear the rear window of fog or frost.

An indicator lamp in the instrument cluster illuminates when the EBL system is on. The BCM contains the EBL system control circuitry, including the timer logic.

NOTE: The EBL system turns off automatically after ten minutes of initial operation. Each following activation cycle of the EBL system will last five minutes.

The EBL system automatically turns off after an initial programmed time interval of about ten minutes, as long as the ignition is left in the Run position. If a rear window defogger switch is pressed to on again after the initial time interval has expired, the EBL system will automatically turn off after about five minutes. The EBL system will also turn off if the ignition is set to any position other than Run, or by manually pressing the rear window defogger switch a second time.

The rear window defogger switch is diagnosed using a scan tool A L L Diagnostic Trouble Codes ( DTC ).

The rear window defogger switch cannot be adjusted or repaired. If the rear window defogger switch is inoperative or damaged, the entire upper accessory switch pod must be replaced Instrument Cluster Switch Pod - Removal.