Lexus GS300/400 (2000 year). Service manual — part 82

I04038

I04039

BE–42

–

BODY ELECTRICAL

HEADLIGHT AND TAILLIGHT SYSTEM

2343

8 – Ground

Headlight dimmer switch HIGH beam or FLASH

Continuity

1 – Ground

Ignition switch LOCK or ACC

No voltage

1 – Ground

Ignition switch ON or START

Battery positive voltage

5 – Ground

Engine Stop

No voltage

5 – Ground

Engine Running

Battery positive voltage

7 – Ground

Constant

Battery positive voltage

9 – Ground

Constant

Battery positive voltage

If circuit is specified, try replacing the relay with a new one.
If circuit is not as specified, inspect the circuits connected to oth-
er parts.

16.

INSPECT AUTOMATIC LIGHT CONTROL
AUTO ON:

(a)

Turn the ignition switch ON.

(b)

Turn the light control switch to AUTO.

(c)

Gradually cover the top of the sensor.

(d)

Check the accessory lights and the headlights should turn
ON.

17.

INSPECT AUTOMATIC LIGHT CONTROL
AUTO OFF:

(a)

Gradually expose the sensor.

(b)

Check the headlights and the accessory lights should turn
OFF.

18.

INSPECT LIGHT–OFF CONDITION

(a)

Turn the ignition switch ON.

(b)

Gradually cover the top of the sensor.
Lights auto ON:

(c)

Check that the lights go off under the following conditions.
(1)

Light control switch is OFF.

(2)

The area surrounding the sensor gets bright.

(3)

The driver’s door is opened with the ignition switch
OFF.

I01254

Wire Harness Side

4

3

2

1

–

BODY ELECTRICAL

HEADLIGHT AND TAILLIGHT SYSTEM

BE–43

2344

19.

INSPECT LIGHTS–ON CONDITION

(a)

Open the driver’s door while the ignition switch is OFF.

(b)

Turn the light control switch to AUTO leaving the door
open and cover the top of the sensor, and verify that the
lights go on when the ignition switch is turned ON.

20.

INSPECT AUTOMATIC LIGHT CONTROL SENSOR
CIRCUIT
Connector disconnected:

Disconnect the connector from the sensor and inspect the con-
nector on the wire harness side, as shown in the table.

Tester connection

Condition

Specified condition

3 – Ground

Constant

Continuity

1 – Ground

Ignition switch LOCK or ACC

No voltage

1 – Ground

Ignition switch ON

Battery positive voltage

4 – Ground

Ignition switch LOCK or ACC

No voltage

4 – Ground

Ignition switch ON

5.2 – 9.0 V

If circuit is as specified, perform the inspection on the following
page.
If the circuit is not as specified, inspect the circuit connected to
other parts.

I01255

1

2

3

4

From Back Side

BE–44

–

BODY ELECTRICAL

HEADLIGHT AND TAILLIGHT SYSTEM

2345

21.

INSPECT AUTOMATIC LIGHT CONTROL SENSOR
CIRCUIT
Connector connected

Connect the wire harness side connector to the sensor and in-
spect wire harness side connector from the back side, as
shown.
HINT:

Ignition switch ON.

Light control switch AUTO.

Vehicle’s surroundings are bright.

Tester connection

Condition

Specified condition

3 – Ground

Constant

Continuity

1 – Ground

Ignition switch LOCK or ACC

No voltage

1 – Ground

Ignition switch ON

9.5 V or more

Vehicle is under the direct sun light.

(Sensor is not covered)

Taillight and Headlight are ON.

If circuit is as specified, try replacing the sensor with a new one.
If the circuit is not as specified, inspect the circuit connected to
other parts.

BE0HB–04

I07736

Adjusting Bolt
(High–Beam Headlight
Horizontal Direction)

Adjusting Bolt
(High–Beam Headlight
Vertical Direction)

Beam Angle Gauge
(Vertical Alignment)

Adjusting Bolt A
(Low–Beam Headlight
Vertical Direction)

Adjusting Bolt B
(Low–Beam Headlight
Horizontal Direction)

Adjusting Bolt
(High–Beam Headlight
Horizontal Direction)

Adjusting Bolt
(High–Beam Headlight
Vertical Direction)

Adjusting Bolt A
(Low–Beam Headlight
Vertical Direction)

Adjusting Bolt B
(Low–Beam Headlight
Horizontal Direction)

Headlight Beam Level Control Actuator

Light Control ECU

Headlight Beam Level Control ECU
(Left side only)

–

BODY ELECTRICAL

HEADLIGHT AND TAILLIGHT SYSTEM

BE–45

2346

ADJUSTMENT