2000 LEXUS GS400 relay

I05029
1 23 4 5
6 78 9 10
± BODY ELECTRICALPOWER SOURCE
BE±29
2330 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
6. INSPECT PASSENGER COWL SIDE RELAY BLOCK
CIRCUIT
Remove the relay from the relay block and inspect the connec-
tor on relay block side.
Relay Tester connectionConditionSpecified condition
DEF 1 ± GroundConstantBattery positive voltage
HEATER 6 ± GroundConstantBattery positive voltage
If the circuit is not as specified, inspect the circuits connected
to other parts.

BE0N6±04
I05587
2 5
I05580
2 5
Z08688
2 13
45 768 Wire Harness Side
± BODY ELECTRICALANTENNA
BE±225
2526 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSPECTION
1. Auto Antenna Models:
INSPECT ANTENNA MOTOR
(a) Connect the positive (+) lead from the battery to terminal
2 and the negative (±) lead to terminal 5.
(b) Check that the motor turns (moves upward).
NOTICE:
These tests must be done quickly (within 3 ± 5 seconds) to
prevent the coil from burning out.
(c) Then, reverse the polarity, check that the motor turns the
opposite way (moves downward).
NOTICE:
These tests must be done quickly (within 3 ± 5 seconds) to
prevent the coil from burning out.
2. Auto Antenna Models:
INSPECT ANTENNA MOTOR CONTROL RELAY CIR-
CUIT
Disconnect the connector from the relay and inspect the con-
nector on wire harness side, as shown in the chart below.
Tester connectionConditionSpecified condition
7 ± GroundConstantContinuity
1 ± GroundIgnition switch ACC or ON,
and radio switch ON and OthersNo voltage
1 ± GroundIgnition switch ACC or ON,
and radio switch ON and AMBattery positive voltage
2 ± GroundIgnition switch ACC or ON,
and radio or tape or CD switch OFFNo voltage
2 ± GroundIgnition switch ACC or ON,
and radio or tape or CD switch ONBattery positive voltage
3 ± GroundConstantBattery positive voltage
4 ± GroundIgnition switch ACC or ON,
and radio switch ON and OthersNo voltage
4 ± Ground
Ignition switch ACC or ON,
and radio switch ON and
AM or FM (87.9 ± 96.0 MHz)
Battery positive voltage
5 ± GroundIgnition switch ACC or ON,
and radio switch OFFNo voltage
5 ± GroundIgnition switch ACC or ON,
and radio switch ONBattery positive voltage

BE±226
± BODY ELECTRICALANTENNA
2527 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)6 ± Ground
Ignition switch ACC or LOCKNo voltage
6 ± GroundIgnition switch ONBattery positive voltage
8 ± GroundIgnition switch LOCKNo voltage
8 ± GroundIgnition switch ACC or ONBattery positive voltage
If circuit is as specified, replace the relay.

BE0FY±09
I01377
Horn
Horn Switch Engine Room No.1
Junction Block

HORN Fuse
Theft Deterrent Horn
Engine Room No.2
Junction Block

Horn Relay
± BODY ELECTRICALHORN SYSTEM
BE±249
2550 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
HORN 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.

I01200
2 1
35
2 5
1 3
± BODY ELECTRICALHORN SYSTEM
BE±251
2552 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
4. INSPECT HORN 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 HORN RELAY CIRCUIT
(See page BE±21)

BE19B±01
± BODY ELECTRICALTROUBLESHOOTING
BE±3
2304 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
TROUBLESHOOTING
PROBLEM SYMPTOMS TABLE
IGNITION SWITCH AND KEY UNLOCK WARNING SWITCH
This system uses the multiplex communication system, so check diagnosis system of the multiplex commu-
nication system before you proceed with troubleshooting.
Ignition Switch:
SymptomSuspect AreaSee page
Ignition switch is not set to each position.4. Ignition switch
5. Power source circuitBE±31
±
Key Unlock Warning Switch:
SymptomSuspect AreaSee page
Key unlock warning system does not operate.
(The buzzer does not sound when the driver's door is opened with
the ignition OFF and key inserted)1. Key Unlock Warning Switch
2. Door Courtesy Switch
3. Wire HarnessBE±31
BE±60
±
Key unlock warning system does not operate.
(The buzzer sounds when the ignition key is ACC or ON)1. Ignition Switch
2. Wire HarnessBE±31
±
HEADLIGHT AND TAILLIGHT SYSTEM:
This system uses the multiplex communication system, so check diagnosis system of the multiplex commu-
nication system before you proceed with troubleshooting.
HINT:
To inspect the bulb and light control ECU, replace them with the ones working normally and judge whether
they work normally or not.
SymptomSuspect AreaSee page
ºAutomatic light control systemº does not operate.
1. Automatic Light Control Sensor
2. Light Control Switch
3. Door Courtesy Switch
4. Wire Harness
5. Body No.2 ECUBE±37
BE±37
BE±60
±
DI±820
Auto turn±off system does not operate when the driver's door is
opened.1. Drivers Door Courtesy SwitchBE±60
Auto turn±off system:
Headlight and taillight do not come on.1. Body ECU No.2
2. Wire HarnessDI±820
±
Auto turn±off system:
Headlight and taillight stay on.1. Body ECU No.2
2. Wire HarnessDI±820
±
USA:
SymptomSuspect AreaSee page
Only one headlight comes on.
1. Bulb
2. *Light Control ECU
3. Wire Harness±
±
±
ºLO±Beamº does not light (All).
1. Headlight Control Relay
2. *Light Control ECU
3. Wire HarnessBE±37
±
±
ºLO±Beamº does not light (One side).
1. Bulb
2. H±LP L±LWR Fuse
3. H±LP R±LWR Fuse
4. *Light Control ECU
5. Wire Harness±
BE±21
BE±21
±
±
ºHI±Beamº does not light (All).1. Headlight Dimmer Switch
2. Wire HarnessBE±37
±

BE±4
± BODY ELECTRICALTROUBLESHOOTING
2305 Author: Date:
2000 LEXUS GS300/GS400 (RM718U) ºHI±Beamº does not light (One side).
1. Bulb
2. H±LP L±UPR Fuse
3. H±LP R±UPR Fuse
4. Wire Harness±
BE±21
BE±21
±
ºFlashº does not light.
1. H±LP L±UPR Fuse
2. H±LP R±UPR Fuse
3. Headlight Dimmer Switch
4. *Light Control ECU
5. Wire HarnessBE±21
BE±21
BE±37
±
±
ºFlashº does not light.
1. Bulb
2. *Light Control ECU
3. Wire Harness±
±
±
Headlight does not come on.
1. Headlight Control Relay
2. Light Control Switch
3. *Light Control ECU
4. Wire HarnessBE±37
BE±37
±
±
Headlight does not come on.
1. Bulb
2. *Light Control ECU
3. Wire Harness±
±
±
Headlight flickers.
1. Bulb
2. *Light Control ECU
3. Wire Harness±
±
±
Headlight is dark.
1. Bulb
2. *Light control ECU
3. Wire Harness±
±
±
Only one taillight comes on.1. Bulb
2. Wire Harness±
±
Taillight does not come on.
(Headlight is normal)
1. TAIL Fuse
2. GAUGE Fuse
3. Taillight Control Relay
4. Light Failure Relay
5. Light Control Switch
6. Wire HarnessBE±21
BE±21
BE±37
BE±92
BE±37
±
Taillight does not come on.
(Headlight does not light)1. Light Control Switch
2. Wire HarnessBE±37
±
Rear combination light does not come on.
1. Light Failure Relay
2. Wire Harness
3. BulbBE±92
±
±
*: HID Type
CANADA:
SymptomSuspect AreaSee page
Only one headlight comes on.
1. Daytime Running Light No.2, 3, 4 Relay
2. Daytime Running Light Main Relay
3. Bulb
4. *Light Control ECU
5. Wire HarnessBE±37
BE±37
±
±
±
ºLO±Beamº does not light (All).
1. Headlight Control Relay
2. *Light Control ECU
3. Wire HarnessBE±37
±
±
ºLO±Beamº does not light (One side).
1. Bulb
2. H±LP L±LWR Fuse
3. H±LP R±LWR Fuse
4. *Light Control ECU
5. Wire Harness±
BE±21
BE±21
±
±

± BODY ELECTRICALTROUBLESHOOTING
BE±5
2306 Author: Date:
2000 LEXUS GS300/GS400 (RM718U) ºHI±Beamº does not light (All).
1. Headlight Dimmer Switch
2. Daytime Running Light Main Relay
3. Wire HarnessBE±37
BE±37
±
ºHI±Beamº does not light (One side).
1. Bulb
2. H±LP L±UPR Fuse
3. H±LP R±UPR Fuse
4. Daytime Running Light No.3 Relay
5. Wire Harness±
BE±21
BE±21
BE±37
±
ºFlashº does not light.
1. Headlight Dimmer Switch
2. Daytime Running Light Main Relay
3. Wire HarnessBE±37
BE±37
±
Headlight does not come on.
1. Headlight Control Relay
2. Daytime Running Light Main Relay
3. Daytime Running Light No.2, 3, 4 Relay
4. Headlight Dimmer Switch
5. Light Control Switch
6. Wire Harness
7. *Light Control ECU
8. BulbBE±37
BE±37
BE±37
BE±37
BE±37
±
±
±
Headlight does not come on with light control switch in HEAD.
1. Light Control Switch
2. *Light Control ECU
3. Wire HarnessBE±37
±
±
Headlight does not go out with light control switch in OFF.
1. Headlight Control Relay
2. *Light Control ECU
3. Wire HarnessBE±37
±
±
Headlight flickers.
1. Bulb
2. *Light Control ECU
3. Wire Harness±
BE±37
±
Headlight is dark.
1. Bulb
2. *Light control ECU
3. Wire Harness±
±
±
Taillight does not come on with light control switch in TAIL.
1. Taillight Control Relay (Instrument Panel J/B)
2. Light Control Switch
3. Wire HarnessBE±37
±
±
Taillight does not go out with light control switch in OFF.
1. Taillight Control Relay
2. Light Control Switch
3. Wire HarnessBE±37
BE±37
±
Headlight does not come on with engine running and light control
switch in OFF.
1. ECU±B Fuse
2. GAUGE Fuse
3. Daytime Running Light Main Relay
4. Daytime Running Light No.2, 3, 4 Relay
5. Generator L Terminal
6. Parking Brake Switch
7. Wire HarnessBE±21
BE±21
BE±37
BE±37
DI±853
BE±92
±
*: HID Type