1991 LEXUS SC400 relay

Parts Replacement ± Taillights
(Clearance Light)
REPLACEMENT OF CLEARANCE LIGHT
(See page BE±37)
HINT: Replacement of Headlight (LO±Beam).
(FRONT SIDE MARKER LIGHT)
REPLACEMENT OF FRONT SIDE
MARKER LIGHT
1. REMOVE FRONT SIDE MARKER LIGHT (a) Disconnect negative (±) terminal from the battery.
CAUTION: Work must be started after approx.20
seconds from the time the ignition switch is turned to the
ºLOCKº position and negative (±) terminal cable is
disconnected from the battery.
(b) Remove fender liner. BO±92)
(c) Remove two nuts.
(d) Remove front side marker light from bumper.
(e) Disconnect connector.
2. INSTALL FRONT SIDE MARKER LIGHT For installation, follow the removal procedure in reverse.
(Light Failure Sensor)
See page BE±62
(Integration Relay)
See page BE±49
(Rear Combination Assembly)
REPLACEMENT OF REAR
COMBINATION LIGHT ASSEMBLY
1. REMOVE REAR COMBINATION LIGHT ASSEMBLY
(a)Disconnect negative (±) terminal from the battery.
CAUTION: Work must be started after approx. 20
seconds from the time the ignition switch is turned to the
ºLOCKº position and negative (±) terminal cable is
disconnected from the battery.
±
BODY ELECTRICAL SYSTEM Lighting SystemBE±55
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Parts Inspection ± Taillights
(Combination Switch Assembly)
(See page BE±46
HINT: Inspect light control switch.
(Taillight Control Relay)
REMOVAL AND INSTALLATION OF
TAILLIGHT CONTROL RELAY
(See page BE±16)
INSPECTION OF TAILLIGHT CONTROL
RELAY
INSPECT TAILLIGHT CONTROL RELAY
(Continuity)
Inspect relay continuity between terminals.
If continuity is not as specified, replace the relay.
(Relay Circuit)
(See page BE±20)
±
BODY ELECTRICAL SYSTEM Lighting SystemBE±57
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Troubleshooting
Taillight System
You will find the cause of troubles more easily using the table well shown \
below. In this table, the numbers indi-
cate the order priority of the causes in troubles. Check each part in the o\
rder shown. If necessary, replace the
parts.
See page
BE±4,20BE±20 ,57BE±46BE±49BE±62BE±79BE±4,20
±
BE±6
±
Trouble
Part name
TAIL FuseTaillignt Control RelayLight Control SwitchIntegration RelayLight Failure SensorDoor CourtesyGAUGE FuseWire HarnessBulbOther Parts
Taillight does not light. (Headlight does
not light.) 12 3
SA
Taillight does not light. (Headlight is
normal.)12345
US
A
Only one light does not light. (Taillight) 2 1 U
Rear combination light does not light. 213
ªLight Auto Turn±Off Systemº does
not operate. 1432
Taillight does not light. (Headlight is
does not light.) 123
Taillight does not light. (Headlight is
normal.)12345
Only one light does not light. (Taillight) 21
ARear combination light does not light. 213
ANADA
ªLight Auto Turn±Off Systemº does
not operate. 1423
CA
N
Taillight does not light with light control
SW in TAIL123
Taillight does not go out with light
control SW in OFF1324
Headlight and Taillight do not light with
engine running and light control SW in
OFF
213*14
*1:
Alternator
L
Terminal
BE±58±
BODY ELECTRICAL SYSTEM Lighting System
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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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(TURN SIGNAL AND HAZARD WARNING
LIGHT SYSTEM)
Description ± TURN SIGNAL AND
HAZARD WARNING LIGHT SYSTEM
The component parts of this system and their function are as shown in the f\
ollowing table.
Parts NameFunction
Turn Signal SwitchSwitches current from the turn signal flasher to the left side or right \
side.
Hazard Warning
SwitchModifies the circuit to the flasher relay and turn signal switch in acco\
rdance with the
respective switch positions.
Turn Signal FlasherReceives current from the hazard warning switch and flashes the turn sig\
nal lights by
switching the current to the lights ON and OFF.
PARTS LOCATION ± TURN SIGNAL
±
BODY ELECTRICAL SYSTEM Lighting SystemBE±65
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(ILLUMINATION LIGHT SYSTEM)
DESCRIPTION ± ILLUMINATION LIGHT
SYSTEM
The component parts of this system and their function are described in the \
following table.
Parts NameFunction
Rheostat LightIn order to adjust the degree of illumination light, the resistance valu\
e of the built±in variableg
Control Volume
jg g,
resistor is sent to the combination meter and rheostat light control.
Integration RelayDuring daytime running light operation this prevents current flow to the\
rheostat light controlgy
(Daytime Running
gy gg g
to stop each illumination from lighting up. When the light control switc\
h is at TAIL or HEAD,(y g
Light Relay: Canada)
gg g
current is sent to the rheostat light control.
PARTS LOCATION
±
BODY ELECTRICAL SYSTEM Lighting SystemBE±71
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(GLOVE BOX LIGHT SWITCH)
REMOVAL AND INSTALLATION OF
GLOVE BOX LIGHT SWITCH
1. REMOVE GLOVE BOX LIGHT SWITCH(a) Remove glove compartment.
(See page BO±112)
(b) Release two tabs and remove switch.
2. INSTALL GLOVE BOX LIGHT SWITCH For installation, follow the removal procedure in reverse.
INSPECTION OF GLOVE BOX LIGHT
SWITCH
INSPECT GLOVE BOX LIGHT SWITCH
(Continuity)
Inspect the switch continuity between terminals.
If continuity is not as specified, replace the switch.
(Switch Circuit)
Disconnect the connector from the switch and inspect the
connector on the wire harness side as shown.
Check forTester connectionConditionSpecified value
Continuity2±GroundConstantContinuity
Voltage1±GroundLight control switch posi-OFFNo voltageVoltage1±Groundg
tionTAIL or HEADBattery positive voltage
If the circuit is not as specified, refer to BE±76 wiring diagram
and inspect the circuits connected to other parts.
(INTEGRATION RELAY)
(See page BE±49 )
(TAILLIGHT CONTROL RELAY)
(See page BE±57 )
BE±74
±
BODY ELECTRICAL SYSTEM Lighting System
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(INTERIOR LIGHT SYSTEM)
Description ± INTERIOR LIGHT SYSTEM
The component parts of this system and their function are as shown in the f\
ollowing table.
Parts NameFunction
Integration RelayFades out some of the interior lights in accordance with signals from th\
e door courtesy
switch and outside handle switch. (Illuminated Entry System)
Door Courtesy SwitchCreates a closed circuit when the doors are opened lighting each courtes\
y light, etc. Also
detects when the door is open and sends the appropriate signals to the i\
ntegration relay.
PARTS LOCATION ± INTERIOR LIGHT
BE±76±
BODY ELECTRICAL SYSTEM Lighting System
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