2000 LEXUS GS400 Service Repair Manual

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.

I04046
Wire Harness Side BE±58
± BODY ELECTRICALTURN SIGNAL AND HAZARD WARNING SYSTEM
2359 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
6. INSPECT TURN SIGNAL FLASHER CIRCUIT
Disconnect the connector from the combination switch and in-
spect the connector on the wire harness side, as shown.
Tester connectionConditionSpecified condition
2 ± GroundConstantContinuity
3 ± GroundConstantContinuity
5 ± GroundTurn signal switch RIGHT or OFFNo continuity
5 ± GroundTurn signal switch LEFTContinuity
6 ± GroundTurn signal switch LEFT or OFFNo continuity
6 ± GroundTurn signal switch RIGHTContinuity
7 ± GroundConstantContinuity
8 ± GroundHazard warning switch OFFNo continuity
8 ± GroundHazard warning switch ONContinuity
1 ± GroundIgnition switch LOCK or ACCNo voltage
1 ± GroundIgnition switch ONBattery positive voltage
4 ± GroundConstantBattery positive voltage
If circuit is as specified, replace the relay.
If circuit is not as specified, inspect the circuits connected to oth-
er parts.

BE0GY±05
I01354
Front Personal Light
Rear Personal Light
Door Courtesy Light
Licence Plate Light Luggage Compartment Light
Door Courtesy Lights
Luggage Compartment
Courtesy Switch
Door Courtesy Light
Vanity Light
Vanity Light
Rheostat Light Control
Glove Compartment
Door Courtesy Light
Glove Compartment
Door Courtesy Switch
Passenger Side Junction Block

DOME Fuse

Body ECU No.1
Driver Side Junction Block

Body ECU No.2
Luggage
Compartment
Key Lock and
Unlock Switch
Rear Personal Light Rear Personal Light
± BODY ELECTRICALINTERIOR LIGHT SYSTEM
BE±59
2360 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INTERIOR LIGHT SYSTEM
LOCATION

I04047
DOOR OFF ON
DOOR OFF ON w/ Sliding Roof w/o Sliding Roof
BE0GZ±03
I04048
Wire Harness Side BE±60
± BODY ELECTRICALINTERIOR LIGHT SYSTEM
2361 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSPECTION
1. INSPECT FRONT PERSONAL LIGHT SWITCH CONTI-
NUITY
Switch positionTester connectionSpecified condition
Interior light switch
OFF (Lever switch)±No continuity
Interior light switch
DOOR (Lever switch)1 ± 3Continuity
Interior light switch
ON (Lever switch)1 ± 2Continuity
*Personal light OFF
(Push switch)±No continuity
*Personal light ON
(Push switch)1 ± 2Continuity
*: Set the interior light switch to OFF or DOOR.
If continuity is not as specified, replace the light assembly or
bulb.
2. INSPECT FRONT PERSONAL LIGHT SWITCH CIR-
CUIT
(See page DI±843)
Disconnect the connector from the switch and inspect the con-
nector on the wire harness side, as shown.
Tester connectionConditionSpecified condition
2 ± GroundConstantContinuity
1 ± GroundConstantBattery positive voltage
If circuit is not as specified, inspect power source or wire har-
ness.

I04049
I04048
Wire Harness Side
I04050
21
OFFON
± BODY ELECTRICALINTERIOR LIGHT SYSTEM
BE±61
2362 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
3. INSPECT REAR PERSONAL LIGHT SWITCH CONTI-
NUITY
Switch positionTester connectionSpecified condition
Room light switch
OFF and door closed±No continuity
Room light switch
ON and door closed1 ± 2Continuity
Room light switch OFF or
ON and door opened1 ± 3Continuity
If continuity is not as specified, replace the light assembly or
bulb.
4. INSPECT REAR PERSONAL LIGHT SWITCH CIRCUIT
Disconnect the connector from the switch and inspect the con-
nector on the wire harness side, as shown.
Tester connectionConditionSpecified condition
2 ± GroundConstantContinuity
1 ± GroundConstantBattery positive voltage
If circuit is not as specified, inspect power source or wire har-
ness.
5. INSPECT VANITY LIGHT CONTINUITY
Switch positionTester connectionSpecified condition
OFF (closed)±No continuity
ON (opened)1 ± 2Continuity
If continuity is not as specified, replace the vanity light assembly
or bulb.