Description & Operation

NOTE: Rear window defogger relay may also be referred to as Electronic Back-Light (EBL) relay.

System consists of a rear glass with vertical bus bars and a series of horizontal grid lines on inside surface. The Body Control Module (BCM) operates a relay located in the trunk. A defogger control switch and timer relay are integrated in A/C-heater control head on vehicles with Manual Temperature Control (MTC). On vehicles with Automatic Temperature Control (ATC), defogger control switch and timer relay are integrated in ATC control head. All vehicles equipped with electrically-heated rear window defogger use a 90-amp generator.

A fusible link, located in charging circuit, provides protection for the heated grid circuit. The relay control circuit is protected by a fuse. When defogger switch is on, current is directed to rear window defogger grid lines. The grid lines heat rear glass to clear fog or frost. Rear window defogger is not meant to melt snow. Remove snow before turning on defogger.

Actuating the control switch energizes circuit, allowing current to flow through grid lines for 15 minutes. Each subsequent actuation provides a 7 1/2-minute current flow until either defogger or ignition is turned off. An indicator light, located on control switch, illuminates when rear window defogger is turned on.