Headlamps

The headlamps may be turned on in three different ways. First, when the headlamp switch is placed in the ON position, for normal operation. Second, With the twilight switch placed in the ON position, for Automatic Lamp Control (ALC). And third, with the twilight switch placed in the ON position, with the windshield wipers ON in daylight conditions, after a 6 second delay. During ALC control the headlamps will be in Daytime Running Lamp (DRL) operation in daylight conditions, or low beam operation in low light conditions. The Dash Integration Module (DIM) provides battery positive voltage to the signal circuits of the headlamp switch. The signal circuits include the headlamp on input, the Flash-To-Pass feature, and the high beam input.

With the headlamp switch in the ON position, a ground path is available for the headlamp switch signal circuit of the DIM through the headlamp switch. The DIM provides ground to either the relay control of the low beam circuit or the high beam circuit. The position of the dimmer switch determines which relay control has ground. The DIM supplies battery positive voltage to the relay control circuits, if the headlamps are necessary. The underhood fuse block supplies battery positive voltage to both relay switch circuits. When the low beam relay control is energized, current flow is to both low beam fuses and to the low beam headlamps. The headlamps have ground at G103 and at G401. When the high beam relay control is energized, current flow is to both high beam fuses and to the high beam headlamps. The high beam circuit is divided into a left and right side circuit. The current flow of the left high beam is from the fuse to the left high beam lamp. From the lamp, the current flows to the normally-closed contact of the daytime running lamp (DRL) relay to G103. The current flow of the right high beam is from the fuse to the right high beam lamp. From the lamp, the current flow is to ground at G401. When the headlamp dimmer switch lever is pulled toward the driver, the Flash-To-Pass switch closes. This grounds the DIM Flash-To-Pass input. In response to this input, the DIM energizes the high beam relay. Both high beams remain on until the driver releases the switch handle. If the low beam headlamps were on during a Flash-To-Pass operation, the low beams remain on. The headlights may be switched to high beam with the opposite movement of the dimmer switch lever.

If the headlight switch is left in the ON position, the inadvertent power control feature will turn off the headlights 10 minutes after the ignition switch is turned to the OFF position. If the driver places the headlight switch in the ON position after the ignition switch has been turned OFF, or if the ignition switch is in the ACCY position, the headlights will remain on until turned off or the battery runs dead.