Headlamp: Description and Operation

System Description

The headlamps are controlled by the headlamp control unit.
Power is supplied at all times
- through 15 A fuse (No.37, located in the fuse and fusible link box)
- to headlamp control unit terminal 7 (for LH headlamp)
- through 15 A fuse (No.36, located in the fuse and fusible link box)
- to headlamp control unit terminal 5 (for RH headlamp).

MANUAL OPERATION

Low Beam Operation
When the combination switch is placed in the LOW BEAM (B) position, with lighting switch in the headlamp
ON (2ND) position, ground is supplied
- to headlamp control unit terminal 9
- through lighting switch terminal 8
- to lighting switch terminal 7
- through body grounds M68, M105 and M130.

Then, power is supplied
- from headlamp control unit terminal 3
- to LH headlamp terminal 3 and
- from headlamp control unit terminal 6
- to RH headlamp terminal 3.
Ground is supplied to each headlamp terminal 2 through body grounds E3, E30 and E50.
With power and ground supplied, the low beam headlamps will illuminate.

High Beam Operation
When the lighting switch is placed in the headlamp ON (2ND) position, ground is supplied to headlamp control unit terminal 9 in the same manner as low beam operation.
With combination switch in the HIGH BEAM (A) position, ground is supplied
- to headlamp control unit terminal 18
- through combination switch terminal 11
- to combination switch terminal 14
- through body grounds E3, E30 and E50.

Then, power is supplied
- from headlamp control unit terminal 8
- to LH headlamp terminal 1 and
- from headlamp control unit terminal 4
- to RH headlamp terminal 1.
Ground is supplied to each headlamp terminal 2 through body grounds E3, E30 and E50.
With power and ground supplied, the high beam headlamps will illuminate.

Power is also supplied
- from headlamp control unit terminal 8 (models without autolamp), 13 (models with autolamp)
- to combination meter terminal 15 for HIGH BEAM indicator.
Ground is supplied to combination meter terminal 9 through body grounds M68, M105 and M130. With power and ground supplied the HIGH BEAM indicator will illuminate.

Flash To Pass Operation
When the combination switch is placed in the FLASH TO PASS (C) position, ground is supplied
- to headlamp control unit terminal 20
- through combination switch terminal 13
- to combination switch terminal 12
- through body grounds E3, E30 and E50.
Then, power is supplied to each headlamp (HIGH) from headlamp control unit to turn on the lamps in the same manner as high beam operation.

AUTOLAMP OPERATION (IF EQUIPPED)

Automatic Illumination
When the ignition switch is in ON position, power is supplied
- through 10 A fuse (No.30, located in the fuse block)
- to headlamp control unit terminal 2.

With power at terminal 2 and lighting switch in AUTO1 or AUTO2 position, the headlamp control unit will monitor the ambient light intensity through terminals 10 and 21. If the autolamp sensor does not detect sufficient light, power is supplied to headlamps in the same manner as low or high beam operation. Headlamp control unit decides to illuminate headlamps (Low or High) according to combination switch position (LOW or HIGH).
At this time, ground is also supplied to tail lamp relay through headlamp control unit terminal 12 to energize tail lamp relay. Then tail lamp relay supplies power to turn on parking, license, tail lamps and illumination. For detailed wiring diagrams, refer to "PARKING, LICENSE, TAIL LAMPS" and "ILLUMINATION".

Shut-off Delay
While the headlamps are lit in the automatic illumination mode, the ignition switch is turned from ON to OFF position and autolamp shut-off delay timer starts. At this time, ground to tail lamp relay is discontinued.
The delay time is set based on the resistance value at headlamp control unit terminal 14. With the timer running, the headlamps remain lit. When the timer reaches the end of its cycle, the headlamps turn off.
Headlamp lighting time can be adjusted from 0 to 3 minutes.

VEHICLE SECURITY SYSTEM
If the vehicle security system is triggered, alarm signal is sent
- to headlamp control unit terminal 19
- from smart entrance control unit terminal 29.
Then headlamp control unit operates to flash the high beams. For details, refer to "VEHICLE SECURITY (THEFT WARNING) SYSTEM".