When the headlamp switch is placed in the ON position, the dash integration module (DIM) Headlamp Switch input is grounded via CKT 103 (WHT).

The twilight delay switch in the headlamp switch is supplied a reference voltage from the instrument panel integration module (IPM) via CKT 1688 (LT BLU/BLK). It is supplied a reference ground from the IPM via CKT 61 (YEL). The switch is a potentiometer that resistance varies as the switch is moved. The IPM receives an input voltage proportional to the resistance of the potentiometer via CKT 1783 (PPL). The IPM sends a class 2 message to the dash integration module (DIM) indicating the on/off status and delay length for the twilight sentinel. With the twilight sentinel in an ON position, the DIM will automatically control the headlamps on/off status depending on the nighttime/daytime status of the ambient light sensor. The DIM will use the twilight sentinel delay length to know how long to keep the headlamps and park lamps on after the ignition switch transitions from ON to OFF during nighttime conditions.

The dash integration module (DIM) supplies battery positive voltage (B+) via CKT 1483 (DK GRN) to the HDLP LO BM relay coil when the headlamps or park lamps need to be on or when the ignition switch is in the ON position. Battery positive voltage (B+) is always supplied to the HDLP LO BM relay switch through the underhood junction block. When the headlamps are to be active, the DIM supplies ground via CKT 1485 (LT BLU) to the low/high beam switch in the headlamp dimmer switch. With the headlamp dimmer switch in the low beam position, the HDLP LO BM relay coil is grounded via CKT 1970 (PNK/WHT). The coil is energized, closing the switch contacts. This supplies battery positive voltage (B+) to the HDLOBML Fuse and HDLOBMR Fuse. HDLOBML Fuse supplies battery positive voltage (B+) via CKT 712 (YEL) to the LH low beam headlamp. HDLOBMR Fuse supplies battery positive voltage (B+) via CKT 312 (TAN/WHT) or (YEL) to the RH low beam headlamp. The LH and RH low beam headlamps are both permanently grounded via CKT 1050 (BLK) to G401, so both low beam headlamps have power and ground, and then light.

The dash integration module (DIM) supplies battery positive voltage (B+) via CKT 1483 (DK GRN) to the HDLP HI BM relay coil when the headlamps or park lamps need to be on or when the ignition switch is in ON position. Battery positive voltage (B+) is always supplied to the HDLP HI BM relay switch through the underhood junction block. When the low beam headlamps are on as described above and then the headlamp dimmer switch is placed in the high beam position, the HDLP HI BM relay coil is grounded via CKT 1969 (BLK/WHT). The coil is energized, closing the switch contacts. This supplies battery positive voltage (B+) to the HDHIBML Fuse and HDHIBMR Fuse. HDHIBML Fuse supplies battery positive voltage (B+) via CKT 711 (DK GRN/WHT) to the LH high beam headlamp. HDHIBMR Fuse supplies battery positive voltage (B+) via CKT 311 (LT GRN/BLK) or (DK GRN/WHT) to the RH high beam headlamp. The RH high beam headlamp is grounded via CKT 1050 (PNK) or (BLK) to G401. The LH high beam headlamp is grounded via CKT 1200 (PNK), DRL Relay when not energized, and CKT 250 (BLK) to G104. Both high beam headlamps have power and ground, and then light. For Export, the LH high beam headlamp is permanently grounded via CKT 250 to G104.

When the headlamps are to be active, the DIM supplies ground via CKT 1970 (PNK/WHT) to the HDLP LO BM relay coil and the low/high beam switch in the headlamp dimmer switch. The relay acts as described above and the low beam headlamps light. When the headlamp dimmer switch is in the high beam position, the HDLP HI BM relay coil is grounded via CKT 1969 (BLK/WHT). The relay acts as described above and the high beam headlamps light in addition to the low beam headlamps.

The flash-to-pass switch is permanently grounded via CKT 350 (BLK) to G200. When the headlamp dimmer switch is pulled toward driver, the flash-to-pass switch in the headlamp dimmer switch closes. The DIM Flash-To-Pass input is grounded via CKT 1484 (PNK/BLK). In response to this input, the DIM supplies ground via CKT 1969 (BLK/WHT) to the HDLP HI BM relay coil. The HDLP HI BM relay has battery positive voltage (B+) as described above. The relay is energized closing the switch contacts. The high beam headlamps are supplied battery positive voltage (B+) as described above. If the low beam headlamps are already on, the will remain on during flash-to-pass. The high beam headlamps will only remain on as long as the switch is held.

The ambient light sensor is supplied a reference ground from the instrument panel integration module (IPM) via CKT 61 (YEL). The sensor is a light sensitive variable resistor that resistance varies as the outside ambient light level changes. The IPM receives an input voltage proportional to the resistance of the resistor via CKT 278 (WHT). The IPM sends a Class 2 message to the dash integration module (DIM) and the rear integration module (RIM) indicating the daytime/nighttime status. The DIM uses the daytime/nighttime status of the ambient light sensor to automatically turn on and off the headlamps with the twilight sentinel on. The RIM uses the daytime/nighttime status of the ambient light sensor to automatically turn on and off the interior courtesy lamps with the interior lamp switch in the AUTO position.

With the daytime running lamps (DRL) programmed to be on, the DRL will operate when the ignition switch is in the ON position, the gear selector lever is out of the PARK position, the headlamp switch is in the OFF position, and the ambient light sensor indicates daytime conditions. Battery positive voltage (B+) is supplied to the DRL relay coil through the underhood junction block. Battery positive voltage is supplied through the underhood junction block FOG/DRL Fuse to the DRL relay normally open switch. The DRL relay normally closed switch receives ground via CKT 250 (BLK) through G104 for normal high headlamp operation. When the dash integration module (DIM) determines that conditions are right for the DRL, the DIM grounds the DRL relay coil via CKT 592 (LT GRN/BLK). This energizes the DRL relay coil and closes the switch to the normally open contact. Battery positive voltage (B+) is supplied to the LH and RH high beam headlamps in series. The high beam headlamps split the voltage and each lights at half intensity. Current will follow the path from the DRL relay to CKT 1200 (PNK), the LH high beam headlamp, CKT 711 (DK GRN/WHT), HDHIBML Fuse, HDHIBMR Fuse, CKT 311 (LT GRN/BLK) or (DK GRN/WHT), the RH high beam headlamp, CKT 1050 (PNK) or (BLK), and G104.

The DRL will operate when the ignition switch is in the ON position, the gear selector lever is out of the PARK position, the headlamp switch is in the OFF position, and the ambient light sensor indicates daytime conditions. Battery positive voltage (B+) is supplied from the rear junction block EXPORT LGT Fuse to the DRL relay coil and switch in the rear compartment relay center via CKT 3140 (ORN). When the dash integration module (DIM) determines that conditions are right for the DRL, the DIM grounds the DRL relay coil via CKT 592 (LT GRN/BLK). This energizes the DRL relay coil and closes the switch contact. Battery positive voltage (B+) is supplied via CKT 691 (GRY) to the LH and RH low beam headlamps through their respective circuits as described above. The low beam headlamps are permanently grounded through CKT 250 (BLK) to G104. The LH and RH low beam headlamps are both permanently grounded through CKT 1050 (BLK) to G401, so both low beam headlamps have power and ground, and then light. The park lamps will also light. Refer to Exterior Lights Circuit Description .