Twilight Sentinel

The twilight sentinel is a feature that provides for the automatic ON-OFF control of the headlamps in response to the level of ambient light. It also keeps the lamps on for a preselected time period after the ignition is turned to the OFF position. The headlamps turn OFF automatically after the preselected time period elapses.

The system consists of the following components:
^ The light sensitive photocell sensor
^ The lamp control module
^ The time delay control with an ON/OFF switch.

The automatic twilight sentinel circuit parallels the regular head/park lamp switch such that the head/park lamp switch must be OFF for automatic control.

The photocell sensor is mounted with the light sensitive surface face up, in the instrument panel trim panel. This positioning exposes the photocell to the skylight through the windshield. The lamp control module is mounted behind the center of the instrument panel, above the HVAC case.

The system turns the headlamps ON under the following conditions:
^ When the ignition switch is in the ON position
^ When the head/park lamp switch is turned OFF
^ When the twilight sentinel control is turned ON
^ Whenever road illumination becomes necessary

As daylight increases in the morning and illumination is no longer needed, the system turns the headlamps OFF.

A time delay circuit in the lamp control module reduces the probability of the headlamps switching ON or OFF while the vehicle passes under viaducts, trees, bright lights, etc. The time is normally 10-30 seconds and may not be adjusted. The variable twilight sentinel control adjusts only the time delay period during which the headlamps remain ON after the ignition is turned to the OFF position. This time delay may be adjusted from 3 seconds to 4 minutes.

Setting the twilight sentinel system control to the OFF position allows normal headlamp operation using the head/park lamp switch. If the head/park lamp switch is moved to the ON position, the headlamps remain ON after the ignition is turned to the OFF position, regardless of the setting on the twilight sentinel control. A warning chime sounds when the driver-side door opens. This chime is a reminder to turn the head/park lamp switch OFF.