LEXUS GS400 2000 Service Repair Manual

I04298
º0º Mark
(Horizontal Alignment)A
B
Lens BE±48
± BODY ELECTRICALHEADLIGHT AND TAILLIGHT SYSTEM
2349 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(e) Horizontal Alignment:
Adjust the headlight aimming.
If the edge of the lens does not match the paper as shown
in the illustration, adjust the lens using bolt B. (See step
5)
HINT:
After adjusting the headlight in vertical direction, check that the
light has been shifted from the adjusted position in the horizon-
tal direction.

BE01R±06
I01351
Headlight Beam Level Control Actuator
Height Control SensorHeadlight Beam Level Control ECU
Driver Side Junction Block

ECU±IG Fuse

GAUGE Fuse
± BODY ELECTRICALHEADLIGHT BEAM LEVEL CONTROL SYSTEM
BE±49
2350 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
HEADLIGHT BEAM LEVEL CONTROL SYSTEM
LOCATION
The vehicle shown in this illustration is ºGS400º.
All components of ºGS300º other than the ones used for engine are same as ºGS400º.

BE0HP±02
I03440
1 2 3
4 5 6
I05442
Wire Harness Side BE±50
± BODY ELECTRICALHEADLIGHT BEAM LEVEL CONTROL SYSTEM
2351 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSPECTION
1. INSPECT HEADLIGHT BEAM LEVEL CONTROL AC-
TUATOR RESISTANCE
(a) Check that continuity exists between terminals 2 and 5.
(b) Check that resistance exists between terminals, as
shown in the chart.
TerminalResistance (W)
2 ± 126 ± 30
2 ± 326 ± 30
2 ± 426 ± 30
2 ± 626 ± 30
5 ± 126 ± 30
5 ± 326 ± 30
5 ± 426 ± 30
5 ± 626 ± 30
If resistance value is not as specified, replace the actuator.
2. INSPECT HEADLIGHT BEAM LEVEL CONTROL ECU
CIRCUIT
Connector disconnected:
Disconnect the connector from the ECU and inspect the con-
nector on the wire harness side, as shown.
Tester connectionConditionSpecified condition
A1 ± A5Ignition switch OFF26 ± 30 W
A1 ± A6Ignition switch OFF26 ± 30 W
A1 ± A7Ignition switch OFF26 ± 30 W
A1 ± A8Ignition switch OFF26 ± 30 W
A4 ± B4Ignition switch ON and light control switch HEADBelow 1.5 V
B1 ± B3Ignition switch OFF3.5 ± 6.5 kW
B5 ± B7Ignition switch OFF3.5 ± 6.5 kW
A4 ± GroundIgnition switch OFFContinuity
If circuit is not as specified, perform the inspection on the follow-
ing pages.

I05442
I05441
13 m sec./ DivisionMotor operating 5V
/ Division
GND Pulse generation
± BODY ELECTRICALHEADLIGHT BEAM LEVEL CONTROL SYSTEM
BE±51
2352 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
3. INSPECT HEADLIGHT BEAM LEVEL CONTROL ECU
CIRCUIT
Connector connected:
Connect the connector from the ECU and inspect the connec-
tor, as shown in the table.
Tester connectionConditionSpecified condition
A1 ± A4Ignition switch ONBattery positive voltage
A1 ± A5Ignition switch ON, when stopping and bouncing
the vehicle.Pulse generation
A1 ± A6Ignition switch ON, when stopping and bouncing
the vehicle.Pulse generation
A1 ± A7Ignition switch ON, when stopping and bouncing
the vehicle.Pulse generation
A1 ± A8Ignition switch ON, when stopping and bouncing
the vehicle.Pulse generation
B2 ± B3Ignition switch ONApprox. 2.5 V
B6 ± B7Ignition switch ONApprox. 2.5 V
B1 ± B3
B5 ± B7Ignition switch ON5 V
If the circuit is not as specified, replace the ECU.
Reference INSPECTION USING OSCILLOSCOPE
HINT:
The correct waveform is as shown in the illustration.

BE0H2±08
I01352
Front Fog Lights
Combination Switch

Front Fog Light Switch Driver Side Junction Block

FOG Fuse

Fog Light Relay

Body ECU No.2
BE±52
± BODY ELECTRICALFOG LIGHT SYSTEM
2353 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
FOG LIGHT SYSTEM
LOCATION
The vehicle shown in this illustration is ºGS400º.
All components of ºGS300º other than the ones used for engine are same as ºGS400º.

I04040
ON
OFF
BE0H3±02
I04034
Wire Harness Side
11
± BODY ELECTRICALFOG LIGHT SYSTEM
BE±53
2354 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSPECTION
1. INSPECT FOG LIGHT SWITCH CONTINUITY
Switch positionTester connectionSpecified condition
OFF±No continuity
ON11 ± 12Continuity
If continuity is not as specified, replace the switch.
2. INSPECT FOG LIGHT SWITCH CIRCUIT
Connector disconnected:
(See page DI±832)
Disconnect the connector from the switch and inspect the con-
nector on the wire harness side, as shown.
Tester connectionConditionSpecified condition
11 ± GroundLight control switch TAIL or HEAD and dimmer
switch LOW or HIContinuity
If circuit is not as specified, inspect the wire harness.

I04035
From Back Side
11
I01200
2 1
35
2 5
1 3
BE±54
± BODY ELECTRICALFOG LIGHT SYSTEM
2355 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
3. INSPECT FOG LIGHT SWITCH CIRCUIT
Connector connected:
Connect the wire harness side connector to the light control and
dimmer switch and inspect the connector from the back side, as
shown.
Tester connectionConditionSpecified condition
11 ± GroundLight control switch HEAD and headlight dimmer
switch LO and fog light switch ONNo voltage
11 ± GroundLight control switch HEAD and headlight dimmer
switch HI or FLASH and fog light switch ONBattery positive voltage
If circuit is not as specified, inspect the wire harness.
4. INSPECT FOG LIGHT RELAY CONTINUITY
ConditionTester connectionSpecified condition
Constant1 ± 2Continuity
Apply B+ between
terminals 1 and 2.3 ± 5Continuity
If continuity is not as specified, replace the relay.
5. INSPECT FOG LIGHT RELAY CIRCUIT
(See page BE±21)

BE0H0±06
I01353
Turn Signal LightsEngine Room No.1
Junction Block

TURN HAZ Fuse
Ignition Switch
Combination Switch

Turn Signal Switch
Hazard Warning Switch
Turn Signal Lights Turn Signal Lights
Driver Side Junction Block

GAUGE FuseCowl Side No.5
Junction Block

Turn Signal Flaher
± BODY ELECTRICALTURN SIGNAL AND HAZARD WARNING SYSTEM
BE±55
2356 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
TURN SIGNAL AND HAZARD WARNING SYSTEM
LOCATION
The vehicle shown in this illustration is ºGS400º.
All components of ºGS300º other than the ones used for engine are same as ºGS400º.

BE0H1±02
I04043
Right turn
Left turn
I04034
Wire Harness Side
2 BE±56
± BODY ELECTRICALTURN SIGNAL AND HAZARD WARNING SYSTEM
2357 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSPECTION
1. INSPECT TURN SIGNAL SWITCH CONTINUITY
Switch positionTester connectionSpecified condition
Left turn1 ± 2Continuity
Neutral±No continuity
Right turn2 ± 3Continuity
If continuity is not as specified, replace the switch.
2. INSPECT TURN SIGNAL SWITCH CIRCUIT
Connector disconnected:
Disconnect the connector from the combination switch and in-
spect the connector on the wire harness side, as shown.
Tester connectionConditionSpecified condition
2 ± GroundConstantContinuity
If circuit is not as specified, inspect the wire harness.

I04035
From Back Side
1 2 3
I04044
I04045
Wire Harness Side
± BODY ELECTRICALTURN SIGNAL AND HAZARD WARNING SYSTEM
BE±57
2358 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
3. INSPECT TURN SIGNAL SWITCH CIRCUIT
Connector connected:
Connect the wire harness side connector to the combination
switch and inspect the connector form the back side, as shown.
Tester connectionConditionSpecified condition
2 ± GroundIgnition switch ON and turn signal switch NeutralNo voltage
1 ± GroundIgnition switch ON and turn signal switch LeftBattery positive voltage e 0 V
3 ± GroundIgnition switch ON and turn signal switch RightBattery positive voltage e 0 V
If circuit is not as specified, inspect the circuits connected to oth-
er parts.
4. INSPECT HAZARD WARNING SWITCH CONTINUITY
Switch positionTester connectionSpecified condition
Switch OFF7 ± 10Continuity
Switch ON7 ± 8Continuity
Illumination circuit2 ± 3Continuity
If continuity is not as specified, replace the switch.
5. INSPECT HAZARD WARNING SWITCH CIRCUIT
(See page DI±814)
Disconnect the switch connector and inspect the connection on
the wire harness side, as shown.
Tester connectionConditionSpecified condition
8 ± GroundConstantContinuity
If circuit is not as specified, inspect the circuits connected to oth-
er parts.