Windshield Defogger Operation

The Heated Wiper De-Ice/Windshield Heater Control System Utilizes A Single Zone Backlight Design, Driven With A Dual Relay Configuration. When The Rear Window Defogger Is Commanded On And The Outside Temperature Is Below 7°C (45°F), The Front Heater And Air Conditioning User Interface Control Will Send A Serial Data Message To The Lighting Control Module To Command The Windshield Defogger Grid To Operate. Also Included In The Front Heater And Air Conditioning User Interface Control Is An Indicator To Inform The Customer With The Current State Of The System. The System Is Only Operational When Engine Is Running Or During Remote Start.

When The Appropriate Conditions Are Met, The Front Heater And Air Conditioning User Interface Control To Send A Serial Data Message To The Lighting Control Module Requesting Windshield Heating Grid Operation. The Lighting Control Module Upon Receipt Of The Serial Data Message Will Provide Voltage To The Coil Side Of The Windshield Heating Grid Relay, This Will Energize The Relay Causing The Relay Switch Contacts To Close Allowing B+ Voltage To Flow Through The Windshield Heating Grid Control Circuit To The Windshield Defogger Grid. The Windshield Defogger Grid Will Activate And Will Turn Off Automatically Depending Upon The Vehicle Speed (Refer To Owner's Manual For Windshield Defogger/Wiper De-Ice Operation Cycles)