relay LEXUS SC300 1991 Service Workshop Manual

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
±
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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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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
±
BODY ELECTRICAL SYSTEM Lighting System
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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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WIPER AND WASHER SYSTEM
DESCRIPTION
The component parts of this system and their functions are described in the\
following table.
Parts NameFunction
Wiper Switch
This switch changes the current from the wiper motor in order to operate\
the wiper motor
at different speeds.
It also has a built±in variable resistor which is used to adjust the \
interval for intermittent
operation.
Wiper RelayThis relay turns the current to the wiper motor ON and OFF at intervals \
and operates the
wipers continuously when the washer switch is ON.
Wiper MotorSwitching of the current at the wiper switch and wiper relay operates th\
e motor at each speed
(HI, LO) and at intervals (INT), thus moving the wiper arms and blad\
es.
Washer SwitchBy grounding current from the washer motor, this switch operates the washer motor.
Washer MotorA pump in this motor pumps washer fluid and sprays it out from the washe\
r nozzles.
Parts Location
BE±84±
BODY ELECTRICAL SYSTEM Wiper and Washer System
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Check forTester connectionConditionSpecified value
Continuity1±GroundConstantContinuity
Voltage2±GroundWiper switch position
(I iti it h ON)
HIGH or MISTBattery positive voltage2±Ground(Ignition switch ON)OFF or INT, LOWNo voltage
3±GroundWiper switch position
(I iti it h ON)
LOW and MISTBattery positive voltage3±Ground(Ignition switch ON)OFF or INT, HIGHNo voltage
6±GroundIgnition switchLOCK or ACCNo voltage6±GroundONBattery positive voltage
If circuit is not as specified, refer to BE±86 wiring diagram and
inspect the circuits connected to other parts.
(Combination Switch)
INSPECT WIPER AND WASHER SWITCH
(See page BE±46)
(Continuity)
Inspect the switch continuity between terminals.
If continuity is not as specified, replace the switch.
(Resistance)
Inspect the switch resistance between terminals.
If resistance value is not as specified, replace the switch.
(Switch Circuit)
Disconnect the switch and wiper relay connector, inspect
each connector on the wire harness side as shown.
±
BODY ELECTRICAL SYSTEM Wiper and Washer SystemBE±91
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