Headlight Doors

CIRCUIT OPERATION:

Battery voltage to open and close the Headlight Doors is applied to terminals B and E of the Headlight Door Module connector C1. The module is grounded at terminal D of connector C1 to G103.


Opening Sequence

When the Light Switch is in HEAD or the Daytime Running Lights (if equipped) are in the night mode, battery voltage is applied to both terminals A and C of the Headlight Door Module connector C1. With battery voltage applied to terminals A and C, the Headlight Door Module energizes its relay. The relay switches move to the the door-open position and voltage is applied to terminal B at the Headlight Door Motors. The motors are controlled by the module switching the ground path. The Headlight Door Motors operate to open the Headlight Doors. When the doors are fully open the module turns off the motors.


Note: Measuring voltage at the motor outputs of the Headlight Door Module is NOT a valid diagnosis procedure. The module rapidly pulses the door motors on (HI) and off (LOW). The pulsing is too rapid to see or measure with a voltmeter. When the pulse signal is low the spinning door motor acts like a generator.

The module can detect the voltage produced by the motor and continues the pulsing signal. Each door motor stops turning when its headlight door is fully open, fully Closed or jammed. Once the motor stalls, no voltage is produced and the module turns off the motor. If a motor runs longer than approximately 6 seconds (disconnected drive linkage) the module will turn off the motor.

Closing Sequence

When the Light Switch is pressed OFF, battery voltage is removed from terminals A and C of connector C1 at the Headlight Door Module. The module de-energizes its relay and the relay switches move to the door-Close position. Battery voltage is applied to terminal A of the Headlight Door Motors. The motors are controlled by the module switching the ground path. The Headlight Door Motors operate to Close the Headlight Doors. When the doors are fully Closed the module turns off the motors.

Note: Measuring voltage at the motor outputs of the Headlight Door Module is NOT a valid diagnosis procedure. See Opening Sequence for additional information.