Heated Glass Element: Description and Operation

Components

^ Heated Windshield Control Module determines when system activates. This module also controls relays, located in Heated Windshield Power Module, that switch output from Heated Windshield Power Module to windshield on and off.

^ Generator supplies 3-phase AC voltage to system.

^ 3-phase AC voltage from Generator is applied to Heated Windshield Power Module, which increases and rectifies this voltage to DC voltage of 50-85 volts.

^ Windshield contains a transparent resistive film which heats when power is supplied to it.

Operation

^ With engine running and heated windshield control switch pressed, terminal A3 of Heated Windshield Control Module is grounded. System on LED lights and engagement sequence begins.

^ Heated Windshield Control Module checks terminal B6 for 11.2 volts or more. This is to ensure sufficient voltage to operate system. While windshield does not draw current from battery, it does reduce amount of charging current available to battery.

^ Heated Windshield Control Module also checks that windshield is not cracked. Crack detection circuit monitors voltage at 2 points in the system. These points are vertical bus and sense trace. A crack in either of these will cause a voltage difference of 10 volts or more, which will shut the system down. If all conditions are met, Heated Windshield Control Module grounds terminal A4 to signal Power Control Module (PCM) to increase engine speed.

^ Heated Windshield Control Module output terminal B1 is then switched to energize relays in Heated Windshield Power Module. Power is then drawn from Generator, increased and rectified by Heated Windshield Power Module and supplied to windshield which then heats.

^ First time system is activated, it will operate for 4 minutes. Any time during same ignition cycle system is reactivated, it will only operate 2 minutes. If gear selector lever is moved out of park or neutral during first activation, system will operate for 2 minutes. If 2 minutes have previously elapsed, system will finish its 4 minute cycle. IF ignition switch is turned off for more than 5 seconds, timing cycle will reset. System may be turned off by depressing heated windshield control switch.