Headlamp: Description and Operation

HEADLAMPS

The headlamps may be turned on in two different ways. First, when the driver places the headlamp switch in the HEADLAMP position, for normal operation. Second, with the headlamp switch placed in the AUTO position, for automatic lamp control (ALC). During ALC control, the headlamps will be in daytime running lamp (DRL) operation in daylight conditions, or low beam operation in low light conditions.

Low Beams-Except ZR2
Battery positive voltage to the headlamp switch is supplied by the HDLP SW fuse in the IP fuse block. When the headlamp switch is in the HDLP position, the headlamp power relay coil is energized. A voltage signal is also sent to the body control module (BCM) signaling that the headlamp switch is activated. The headlamp power relay coil is grounded at G102. When the headlamp power relay is energized, the relay supplies battery voltage to the LT HDLP and RT HDLP fuses. Both low beam headlamps are grounded by the multifunction headlamp dimmer switch in the low beam position through the normally closed headlamp grounding relay in the body relay block to G200.

Low Beams-ZR2
Battery positive voltage to the headlamp switch is supplied by the HDLP SW fuse in the IP fuse block. When the headlamp switch is in the HDLP position, the headlamp power relay coil is energized. A voltage signal is also sent to the body control module (BCM) signaling that the headlamp switch is activated. When the headlamp switch is in the AUTO or PARK position and the ambient light sensor detects darkness, the BCM produces a voltage signal that will also energize the headlamp power relay. The headlamp power relay coil is grounded at G102. When the headlamp power relay is energized, the relay supplies battery voltage to the LT HDLP and RT HDLP fuses. Both low beam headlamps are grounded by the multifunction headlamp dimmer switch in the low beam position through the normally closed daytime running lamp (DRL) relay to G102.

High Beams-Except ZR2
Battery positive voltage to the headlamp switch is supplied by the HDLP SW fuse in the IP fuse block. When the headlamp switch is in the HDLP position, the headlamp power relay coil is energized. A voltage signal is also sent to the body control module (BCM) signaling that the headlamp switch is activated. When the headlamp switch is in the AUTO or PARK position and the ambient light sensor detects darkness, the BCM produces a voltage signal that will also energize the headlamp power relay. The headlamp power relay coil is grounded at G102. When the headlamp power relay is energized, the relay supplies battery voltage to the LT HDLP and RT HDLP fuses. The RH high beam headlamp receives current directly from the RT HDLP fuse. When the headlamp switch is in the HDLP position, the BCM removes the ground path to the headlamp grounding and DRL relay coils. This allows current to flow to the LH high beam headlamp through the normally closed contacts of the DRL relay. Both high beam headlamps are grounded by the multifunction headlamp dimmer switch in the high beam position through the normally closed contacts in the headlamp grounding relay to G200. A ground signal is also sent to the BCM in order to confirm high beam operation.

High Beams-ZR2
Battery positive voltage to the headlamp switch is supplied by the HDLP SW fuse in the IP fuse block. When the headlamp switch is in the HDLP position, the headlamp power relay coil is energized. A voltage signal is also sent to the body control module (BCM) signaling that the headlamp switch is activated. When the headlamp switch is in the AUTO or PARK position and the ambient light sensor detects darkness, the BCM produces a voltage signal that will also energize the headlamp power relay. The headlamp power relay coil is grounded at G102. When the headlamp power relay is energized, the relay supplies battery voltage to the LT HDLP and RT HDLP fuses. Both high beam headlamps are grounded by the multifunction headlamp dimmer switch in the high beam position through the normally closed contacts of the daytime running lamp (DRL) relay to G102.

Headlamp Leveling-Export
Voltage is supplied to the headlamp leveling switch through the IGN E fuse in the underhood fuse block. The headlamp leveling actuators are also powered by the same fuse but from a different terminal location in the underhood fuse block than the headlamp leveling switch. The headlamp leveling switch varies the amount of current to the actuators causing them to move simultaneously up or down to each selected position. Ground for the actuators and the switch are supplied by G203.