low beam LEXUS GS400 2000 Service Repair Manual

± BODY ELECTRICALTROUBLESHOOTING
BE±9
2310 Author: Date:
2000 LEXUS GS300/GS400 (RM718U) Washer fluid does not operate.
Washer Hose and Nozzle±

When wiper switch is in HI position, the wiper blade is in contact
with the body.

When the wiper switch is OFF, the wiper blade does not retract
or the retract position is wrong.
1. Wiper Motor *1
2. Wire harness *1BE±77
±
*1: Inspect wiper arm and blade set positions.
COMBINATION METER
This system uses the multiplex communication system, so check diagnosis system of the multiplex
communication system before you proceed with troubleshooting.
Refer to DI section for warning light or indicator light not described in the table below.
SymptomSuspect AreaSee page
Driver seat belt warning light does not light up.
1. Bulb
2. Driver Buckle Switch CIrcuit
3. Meter Circuit Plate
4. Wire Harness
5. Body No.2 ECU±
BE±92
BE±92
±
DI±820
Passenger seat belt warning light does not light up.
1. Clock System
2. Passenger Buckle Switch CIrcuit
3. Occupant Detection Sensor
4. Meter Circuit Plate
5. Wire Harness
6. Body No.1 ECUBE±227
BE±92
BE±92
BE±92
±
DI±776
SRS warning light does not light up.
1. MPX±B Fuse
2. SRS±B Fuse
3. Bulb
4. Meter Circuit Plate
5. Wire Harness
6. Airbag Sensor AssemblyBE±21
BE±21
±
BE±92
±
DI±550
Hi±beam indicator light does not light up.
1. Bulb
2. Meter Circuit Plate
3. Wire Harness
4. Headlight System±
BE±92
±
BE±3
Turn indicator light does not light up.
1. Bulb
2. Meter Circuit Plate
3. Wire Harness
4. Turn Signal and Hazard Warning System±
BE±92
±
BE±3
ABS warning light does not light up.
1. GAUGE Fuse
2. Bulb
3. Meter Circuit Plate
4. Wire Harness
5. ABS, TRAC and VSC ECUBE±21
±
BE±92
±
DI±387
TRAC warning light does not light up.
1. GAUGE Fuse
2. Bulb
3. Meter Circuit Plate
4. Wire Harness
5. ABS, TRAC and VSC ECUBE±21
±
BE±92
±
DI±473

BE0HA±02
I04033
HI
Flash OFFTAIL HEAD AUTO
LO
± BODY ELECTRICALHEADLIGHT AND TAILLIGHT SYSTEM
BE±37
2338 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSPECTION
1. FAIL±SAFE FUNCTION
(Light Control ECU)
When input error is inspected.
When input voltage is not within the range of operation voltage (9 to 16 V),
lighting of the headlight stops. As soon as the voltage comes within the range,
it lights up again.
However if the input voltage becomes low after lighting up,
sufficient voltage is maintained until light of bulb completely goes off.
When output error is inspected (Open or short).
When light flushing is inspected.
When an error occurs in the output voltage (open or short) or flushing symptom
occurs on the bulb, lighting of the headlight stops, the condition is maintained
until power is turned ON again (headlight dimmer switch OFF " ON).
In this case, it can not be judged whether lighting malfunction is caused by an
output error or other reasons (fuse blown out, etc.).
Check that there is no error in fuse and wiring (including power source) and
replace the bulb in the first place, when the error still appears, replace the light
control ECU.
2. INSPECT LIGHT CONTROL SWITCH CONTINUITY
Switch positionTester connectionSpecified condition
OFF±No continuity
TAIL15 ± 16Continuity
HEAD14 ± 15 ± 16Continuity
AUTO13 ± 16Continuity
If continuity is not as specified, replace the switch.
3. INSPECT HEADLIGHT DIMMER SWITCH CONTINU-
ITY
Switch positionTester connectionSpecified condition
Low beam17 ± 18Continuity
High beam8 ± 17Continuity
Flash8 ± 9 ± 17Continuity
If continuity is not as specified, replace the switch.

I01260
21
3 42
41
3
I01200
2 1
35
2 5
1 3
I04037
Wire Harness Side
h±10±1±A
± BODY ELECTRICALHEADLIGHT AND TAILLIGHT SYSTEM
BE±41
2342 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
11. INSPECT HEADLIGHT DIMMER ( DAYTIME RUNNING
LIGHT NO.2) RELAY CONTINUITY
ConditionTester connectionSpecified condition
Constant1 ± 4
2 ± 4Continuity
Apply B+ between
terminals 2 and 4.1 ± 3 ± 4Continuity
If continuity is not as specified, replace the relay.
12. INSPECT HEADLIGHT DIMMER (DAYTIME RUNNING
LIGHT NO.2) RELAY CIRCUIT
(See page BE±21)
13. INSPECT TAILLIGHT CONTROL 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.
14. INSPECT TAILLIGHT CONTROL RELAY CIRCUIT
(See page DI±845 and BE±21)
15. INSPECT DAYTIME RUNNING LIGHT MAIN RELAY
CIRCUIT
Disconnect the connector from the relay and inspect the con-
nector on the wire harness side.
Tester connectionConditionSpecified condition
2 ± GroundLight control switch OFF or TAILNo continuity
2 ± GroundLight control switch HEADContinuity
4 ± GroundParking brake switch OFF
(Parking brake pedal released)No continuity
4 ± GroundParking brake switch ON
(Parking brake pedal depressed)Continuity
6 ± GroundConstantContinuity
8 ± GroundHeadlight dimmer switch LOW beamNo continuity

I04038
I04039
BE±42
± BODY ELECTRICALHEADLIGHT AND TAILLIGHT SYSTEM
2343 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)8 ± Ground
Headlight dimmer switch HIGH beam or FLASHContinuity
1 ± GroundIgnition switch LOCK or ACCNo voltage
1 ± GroundIgnition switch ON or STARTBattery positive voltage
5 ± GroundEngine StopNo voltage
5 ± GroundEngine RunningBattery positive voltage
7 ± GroundConstantBattery positive voltage
9 ± GroundConstantBattery 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.

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 ELECTRICALHEADLIGHT AND TAILLIGHT SYSTEM
BE±45
2346 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
ADJUSTMENT

I04297
Beam Angle Gauge
(Vertical Alignment)
Acceptable
Range
Bubble
I04298
º0º Mark
(Horizontal Alignment)A
B
Lens BE±46
± BODY ELECTRICALHEADLIGHT AND TAILLIGHT SYSTEM
2347 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
1. ADJUST HEADLIGHT AIMMIMG
(a) Inspect the headslight aimming.
Do the following items before inspection.

Make sure the body around the headlight is
not deformed.

Park the vehicle on a level spot.

The driver gets into the driver's seat and puts
the vehicle in a state ready for driving (with a
full tank).

Bounce the vehicle several times.
(b) Adjust the headlight aimming.

Vertical Alignment:
If the bubble is out of the acceptable range of the
beam angle gauge, adjust it using bolt A.

Horizontal Alignment:
If the edge of the lens does not match º0º mark, ad-
just the lens using bolt B.
HINT:
After adjusting the headlight in vertical direction, check that the
light has been shifted from the adjusted position in the horizon-
tal direction.
2. REPLACE HEADLIGHT
(a) Replace the headlight.
(b) Inspect the headlight aimming.
Do the following items before inspection.

Make sure the body around the headlight is
not deformed.

Park the vehicle on a level spot.

The driver gets into the driver's seat and puts
the vehicle in a state ready for driving (with a
full tank).

Bounce the vehicle several times.

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.

I04253

Meter Circuit Plate ± 2
Combination Meter ECU
SLIP Indicator
TRAC OFF Indicator
Window Washer Level Warning
ABS Warning
VSC Warning
Brake Fluid Level Warning
ECT SNOW Indicator
Low Oil Pressure Warning
ECT PWR Indicator
Discharge Warning
CRUISE MAIN Indicator
Seat Belt Warning
Rear Light Indicator
Headlight Leveling Indicator
SRS Warning
Open Door Warning
Fog Light IndicatorA/T 2 Indicaor
Engine Oil Level Indicator
Malfunction Indicator
Fuel Level Indicator
Headlight Indicator (USA)
Taillight Indicator (CANADA) ODO/
TRIP
Display
PanelIG+
SLIP
TRC OFF
WASHER
ABS
VSC
BRAKE
ECT SNOW
OIL P
ECT PWR
CHARGE
CRUISE
SEAT BELT
Rr LIGHT
HEAD LVL
AIRBAG
SRS +B
DOOR
FR FOG
COM1
SEG30
TEST1
TEST2
TEST3
GroundCHECK
ENG
IG+
FUEL
IG+
BEAM±
BEAM+ SRS +BTAIL A/T R
A/T L
A/T N
A/T D
OIL LVLDIM+
A/T 2
A/T 3
A/T 4F12
A/T PF11
F10
F9
F8
F5
F4
F2
F1
C7
C5
C3
D12
D8 E11
E10
E9
E8
E7
E6
J1
J33
D6
D4Hi±Beam Indicator
D2 E20
E19
E18
E17
E16
E15
E14
E13
E12
E3
E1 E5
E4A/T 3 Indicaor
A/T 4 Indicaor
A/T P Indicaor
A/T R Indicaor
A/T L Indicaor
A/T N Indicaor
A/T D Indicaor
T1
T2
T3
T4
~~
D10 BE±88
± BODY ELECTRICALCOMBINATION METER
2389 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)

I04079
Connector ºCº Connector ºDº
Connector ºFº Connector ºEº
Connector ºGº
1 131 13
1 201 12
± BODY ELECTRICALCOMBINATION METER
BE±93
2394 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
2. INSPECT COMBINATION METER CIRCUIT PLATE
Warning light circuit plate:
(a) Remove meter cover.
(b) Disconnect connectors ºCº, ºDº, ºEº, ºFº and ºGº from the
meter circuit plate and inspect the connectors on the wire
harness side as shown in the table.
Tester connectionCheck indicator lightSpecified condition
D10 (+) ± D12 (±)Fuel level warning lightContinuity
D6 (+) ± D8 (±)Headlight indiactor light (USA)
Taillight indiactor light (CANADA)Continuity
D2 (+) ± D4 (±)Hi±beam indicator lightContinuity
C3 (+) ± C7 (±)Engine oil level warning lightContinuity
C3 (+) ± C5 (±)Malfunction indicator lightContinuity
E19 (±) ± E20 (+)Slip warning lightContinuity
E18 (±) ± E20 (+)TRAC OFF indicator lightContinuity
E17 (±) ± E20 (+)Window washer level warning lightContinuity
E16 (±) ± E20 (+)ABS warning lightContinuity
E15 (±) ± E20 (+)VSC OFF indicator lightContinuity
E14 (±) ± E20 (+)Brake warning lightContinuity
E13 (±) ± E20 (+)ECT SNOW indicator lightContinuity
E12 (±) ± E20 (+)Low oil pressure warning lightContinuity
E11 (±) ± E20 (+)ECT PWR indicator lightContinuity
E10 (±) ± E20 (+)Discharge warning lightContinuity
E9 (±) ± E20 (+)CRUISE MAIN indicator lightContinuity
E8 (±) ± E20 (+)Seat belt warning lightContinuity
E7 (±) ± E20 (+)Rear Lights warning lightContinuity
E6 (±) ± E20 (+)Headlight leveling indiactorContinuity
E4 (+) ± E5 (±)SRS warning lightContinuity
E3 (±) ± E4 (+)Open door warning lightContinuity
F4 (±) ± F12 (+)A/T shift indicator light (L)Continuity
F11 (±) ± F12 (+)A/T shift indicator light (2)Continuity
F10 (±) ± F12 (+)A/T shift indicator light (3)Continuity
F8 (±) ± F12 (+)A/T shift indicator light (P)Continuity

Z03473
Ammeter
Battery
VoltmeterGenerator Disconnect Wire
from Terminal B
B01656
Terminal F
± CHARGING (2JZ±GE)CHARGING SYSTEM
CH±3
1605 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
7. CHECK CHARGE WARNING LIGHT CIRCUIT
(a) Warm up the engine and then turn it off.
(b) Turn off all accessories.
(c) Turn the ignition switch ºONº. Check that the charge warn-
ing light is lit.
(d) Start the engine. Check that the light goes off.
If the light does not go off as specified, troubleshoot the charge
light circuit.
8. INSPECT CHARGING CIRCUIT WITHOUT LOAD
HINT:
If a battery/generator tester is available, connect the tester to
the charging circuit as per manufacturer's instructions.
(a) If a tester is not available, connect a voltmeter and amme-
ter to the charging circuit as follows:

Disconnect the wire from terminal B of the genera-
tor, and connect it to the negative (±) probe of the
ammeter.

Connect the positive (+) probe of the ammeter to
terminal B of the generator.

Connect the positive (+) probe of the voltmeter to
terminal B of the generator.

Ground the negative (±) probe of the voltmeter.
(b) Check the charging circuit as follows:
With the engine running from idling to 2,000 rpm, check
the reading on the ammeter and voltmeter.
Standard amperage: 10 A or less
Standard voltage: 13.2 ± 14.8 V
If the voltmeter reading is more than standard voltage, replace
the voltage regulator.
If the voltmeter reading is less than standard voltage, check the
voltage regulator and generator as follows:

With terminal F grounded, start the engine and
check the voltmeter reading of terminal B.

If the voltmeter reading is more than standard volt-
age, replace the voltage regulator.

If the voltmeter reading is less than standard volt-
age, check the generator.
9. INSPECT CHARGING CIRCUIT WITH LOAD
(a) With the engine running at 2,000 rpm, turn on the high
beam headlights and place the heater blower switch at
ºHIº.
(b) Check the reading on the ammeter.
Standard amperage: 30 A or more
If the ammeter reading is less than the standard amperage, re-
pair the generator.
HINT:
If the battery is fully charged, the indication will sometimes be
less than standard amperage.