bulb LEXUS SC400 1991 Service Owner's Manual

INSPECTION OF LIGHT FAILURE
SENSOR
INSPECT LIGHT FAILURE SENSOR(Relay Circuit)
Disconnect the connector from the sensor and inspect the
connector on the wire harness side as shown.
Check forTester connectionConditionSpecified value
Continuity1±GroundConstant*Continuity
2±GroundConstant*Continuity
3±GroundConstant*Continuity
9±GroundConstant*Continuity
11±GroundConstantContinuity
Voltage3±GroundTail or HeadOFFNo voltage
ONBattery voltage
4±GroundIgnition switchLOCK or ACCNo voltage
ONBattery voltage
7±GroundStop light switchOFFNo voltage
ONBattery voltage
Voltage8±GroundIgnition switchLOCK or ACCNo voltage
ONBattery voltage
*: There is resistance because this circuit is grounded through the bulb*: There is resistance because this circuit is grounded through the bulb.
If circuit is as specified, replace the sensor. If the circuit is not
as specified, refer to BE±60 wiring diagram and inspect the
circuits connected to other parts.
±
BODY ELECTRICAL SYSTEM Lighting SystemBE±63
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Troubleshooting
Stop Light System
You will find the cause of trouble more easily using the table shown. In t\
his table, the numbers indicate the order
priority of the causes in trouble. Check each part in the order shown. If nece\
ssary, replace the parts.
See pagePart
name
Trouble
Stop light does not light up.
Stop light always lights up.
Only one light always lights up.
Only one light does not light up.
BE±4
, 20
BE±61
BE±62
BE±6
STOP Fuse
Stop Light Switch
Light Failure Sensor
Wire Harness
Bulb
BE±64±
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Parts Inspection (Turn and Hazard)
(Combination Switch Assembly)
(See page BE±39)
HINT: Inspect turn signal light switch.
(Turn Signal Flasher)
REMOVAL AND INSTALLATION OF TURN
SIGNAL FLASHER
(See page BE±16 )
INSPECTION OF TURN SIGNAL
FLASHER
INSPECT TURN SIGNAL FLASHER
(Operation)
LHD Side
(a) Connect the positive (+) lead from the battery to terminal
1 and the negative (±) lead to 4.
(b) Connect the two turn signal light bulbs parallel to each other to terminals 3 and 4, check that bulbs flash.
RHD Side
(c) Connect the positive (+) lead from the battery to terminal
1 and the negative (±) lead to 2.
(d) Connect two turn signal light bulbs parallel to each other
to terminals 2 and 5, check that the bulbs flash.
HINT: The turn signal lights should flash 60 to 120 times per
minute.
If one of the front or rear turn signal lights has an open circuit,
the number of flashes will be more than 140 per minute.
If operation is not as specified, replace the flasher.
(Flasher Circuit)
(See page BE±23 )
(HAZARD WARNING SWITCH)
REMOVAL AND INSTALLATION OF
HAZARD WARNING SWITCH
1. REMOVE INSTRUMENT PANEL NO.2 REGISTER
ASSEMBLY
(See page BO±111 )
2. REMOVE HAZARD WARNING SWITCH Remove two screws and hazard warning switch from register.
3. INSTALL HAZARD WARNING SWITCH AND REGISTER
For installation, follow the removal procedure in reverse.
BE±68
±
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INSPECTION OF HAZARD WARNING
SWITCH
INSPECTION HAZARD WARNING SWITCH(Continuity)
Inspect the switch continuity between terminals.
If continuity is not as specified, replace the switch.
(Switch Circuit)
Disconnect the switch connector and inspect the connection
on the wire harness side as shown.
Check forTester connectionConditionSpecified value
Voltage8±GroundConstantBattery positive voltage
10±GroundIgnition switchpositionLOCK or ACCNo voltage10±GroundIgnition switch positionONBattery positive voltage
*12±GroundLight control switchpositionOFFNo voltage*12±GroundLight control switch positionTAIL or HEADBattery voltage
Continuity*13±GroundConstantContinuity
5±GroundConstant*2Continuity
6±GroundConstant*2Continuity
*1: Illumination*2: There is resistance because this circuit is grounded through the bulb.\
If the circuit is not as specified, refer to BE±66 wiring diagram
and inspect the circuits connected to other parts.
±
BODY ELECTRICAL SYSTEM Lighting SystemBE±69
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TROUBLESHOOTING
Turn Signal and Hazard Warning Light
System
You will find the cause of trouble more easily using the table shown below. In this table, the numbers indicate
the order priority of the causes in trouble. Check each part in the order \
shown. If necessary, replace the parts.
See pagePart
name
Trouble
ªHazardº and ªTurnº do not light up.
The flashing frequency is abnormal.
Hazard warning light does not light up.
(Turn is normal.)
Hazard warning light does not light up
in one direction.
*  Turn signal does not light up.
*

Turn signal does not light up.
Turn signal does not light up in one direction.
Only one bulb does not light up.
*
: Combination Meter, Wiper and Washer do not operate.
*  : Combination Meter, Wiper and Washer are normal.
HAZ±HORN Fuse
TURN Fuse
Ignition Switch
Hazard Warning Switch
Turn Signal Flasher
Turn Signal Switch
Wire Harness
Bulb
BE±4
, 21
BE±4
, 20
BE±26
BE±68
BE±68
BE±46
BE±6
BE±70±
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Parts Inspection ± Interior Lights
(Integration Relay)
REMOVAL AND INSTALLATION OF
INTEGRATION RELAY
(See page BE±49 )
INSPECTION OF INTEGRATION RELAY
INSPECT INTEGRATION RELAY
(Relay Circuit/Illuminated Entry System)
Remove the relay from junction block and inspect the con-
nector on the junction block side as shown in the chart.
Check forTester connectionConditionSpecified value
ContinuityA1±GroundDriver's or passenger's courtesyOFF (Door closed)No continuityyA1±Groundgy
switchON (Door opened)Continuity
A4±GroundPassenger's courtesy switchOFF (Door closed)No continuityA4±GroundPassenger's courtesy switchON (Door opened)Continuity
A6±GroundDriver's courtesy switchOFF (Door closed)No continuityA6±GroundDriver's courtesy switchON (Door opened)Continuity
A10±GroundConstantContinuity
VoltageA1±GroundConstant*Battery voltageg
A2±GroundConstant*Battery voltage
A10±GroundInterior light switchON*Battery voltageA10±GroundInterior light switchOFFNo voltage
*: There is resistance because this circuit is grounded through the bulb\
.
If the circuit is as specified, try replacing the relay with a new
one.
If the circuit is not as specified, refer to BE±77 wiring diagram
and inspect the circuits connected to other parts.
BE±78
±
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(Front Personal Light Switch)
REMOVAL AND INSTALLATION OF
FRONT PERSONAL LIGHT
1. REMOVE FRONT PERSONAL LIGHT(a) Release eight tabs and remove the lens.
(b) Remove three screws and separate front personal light.
(c) Disconnect connector and remove front personal light.
2. INSTALL FRONT PERSONAL LIGHT For installation, follow the removal procedure in reverse.
INSPECTION OF FRONT PERSONAL
LIGHT
INSPECT FRONT PERSONAL LIGHT SWITCH(Continuity)
Inspect the light switch continuity between terminals.
If continuity is not as specified, replace the light assembly or
bulb.
(Switch Circuit)
Disconnect the connector from the switch and inspect the
connector on the wire harness side as shown.
Check forTester connectionConditionSpecified value
Voltage3±GroundConstantBattery voltage
Continuity1±GroundConstantContinuity
If circuit is not as specified, inspect power source or wire
harness.
BE±80
±
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(Vanity Light Switch)
REMOVAL AND INSTALLATION OF
VANITY LIGHT SWITCH
1. REMOVE VANITY LIGHT(a) Release two tabs and remove the lens.
(b) Remove two screws and separate the vanity light from sun visor.
(c) Disconnect connector and remove vanity light.
2. INSTALL VANITY LIGHT For installation follow the removal procedure in reverse.
INSPECTION OF VANITY LIGHT
INSPECT VANITY LIGHT SWITCH
(Continuity)
Inspect the vanity light continuity between terminals.
If continuity is not as specified, replace bulb or vanity light.
(Switch Circuit)
Disconnect the connector from the switch and inspect the
connector on the wire harness side as shown.
Check forTester connectionConditionSpecified value
Voltage1±GroundConstantBattery positive voltage
Continuity2±GroundConstantContinuity
If circuit is not as specified, inspect power source or wire har-
ness.
±
BODY ELECTRICAL SYSTEM Lighting SystemBE±81
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TROUBLESHOOTING
Interior Light System
You will find the cause of trouble more easily using the table shown below. In this table, the numbers indicate
the order priority of the causes in the trouble. Check each part in the ord\
er shown. If necessary, replace the parts.
See pageB±4,21BE±79BE±49BE±80BE±81BE±82
±
BE±6
Trouble
Part Name
DOME FuseDoor Courtesy SwitchIntegration RelayFront Personal LightVanity LightLuggage Compartment Door
Courtesy SwitchWire HarnessBulb
Only one interior light does not light up.21
Interior light does not light up. (All)12
ºIlluminated Entry Systemº does not oper-
ate.213
Interior light does not light up.
(in front personal light)231
Front personal light does not light up.231
Rear personal light does not light up.21
Vanity light does not light up.231
Luggage compartment light does not light
up.231
Courtesy light does not light up.231
±
BODY ELECTRICAL SYSTEM Lighting SystemBE±83
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DESCRIPTION
The combination meter has various meters and gauges which show the vehicle'\
s condition, warning lights which
monitor abnormalities in the vehicle and inform the driver, indicator lights which inform the driver of the condition
of each part of vehicle, and a function for illumination and brightness ad\
justment of meters and gauges.
The component parts of this system and their functions are described in \
the following table.
Parts NameFunction
SpeedometerThe speedometer needle moves in accordance with signals from the speed s\
ensor to
indicate the vehicle's speed.
TachometerThe tachometer needle moves in accordance with signals from the igniter \
to indicate the
engine's speed.
Water Temperatrue
GaugeThe water temperature gauge's needle moves in accordance with signals from the send-
er gauge and indicates the temperature of the engine coolant.
Fuel GaugeThe fuel gauge needle moves in accordance with signals from the sender g\
auge, indicat-
ing the amount of fuel remaining in the fuel tank.
OdometerThe odometer counts the total distance traveled by the vehicle in accord\
ance with pulse
signals from the speed sensor.
Twin Trip Switch
The twin trip meter counts the distance traveled by the vehicle in accor\
dance with pulse
signals from the speed sensor. It can be reset using a switch and can be used to switch
between trip meters A and B.
Circuit Plate
This plate contains the circuitry for each meter and gauge and for each \
warning light and
indicator light, as well as an internal engine oil level warning drive c\
ircuit, drive circuits for
the odometer and trip meter and brightness adjustment circuitry for each\
indicator.
Speed SensorMounted in the transmission, this sensor outputs pulse signals to the co\
mbination meter
in accordance with the speed of the output shaft.
Twin Trip SwitchOperation of this switch switches between the A and B trip meters and se\
nds reset sig-
nals to the combination meter.
Water
Temperature Sender
GaugeThis sender converts engine coolant temperatures to a resistance value i\
n signal form to
the combination meter.
Fuel Sender GaugeThis sender converts the level of fuel remaining in fuel tank to resista\
nce value and
sends the resistance value in signal form to combination meter.
Rheostat Light
Control VolumeIn order to adjust the degree of illumination of the combination meter, the resistance val-
ue of the built±in variable resistor is sent to the combination meter\
and rheostat light
control.
Fuel Level Warning
SwitchWhen the level of fuel remaining falls below a predetermined level, cont\
inuity is estab-
lished with this switch, which is built into the fuel sender gauge, caus\
ing a warning light
to light up.
Low Oil Pressure
Warning SwitchThis switch is mounted on the engine block. Continuity is established in\
this switch when
the oil pressure is low, causing a warning light to light up.
Integration Relay (Seat
Belt Warning Relay)
This relay receives current from fuse GAUGE and DOME and is connected to\
each
buckle switch, door courtesy switch, key unlock warning switch and warni\
ng light. As
part of the seat belt warning system, it sounds a chime and lights a war\
ning light when
seat belts are unfastened. As part of the key unlock warning system, it \
sounds a chime
when the set conditions are fulfilled.
Light Failure SensorThis sensor senses when a bulb in rear combination light is burnt out an\
d lights up a
warning light.
BE±96±
BODY ELECTRICAL SYSTEM Combination Meter
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