ignition switch LEXUS SC400 1991 Service Repair Manual

(Integration Relay)
REMOVAL AND INSTALLATION OF
INTEGRATION RELAY
(See page BE±16)
INSPECTION OF INTEGRATION RELAY
INSPECT INTEGRATION RELAY
(Relay Circuit/Light Auto Turn Off System)
Remove the relay from junction block and inspect the con-
nectors on the wire harness and junction block side as shown
in the chart.
(USA)
Check forTester connectionConditionSpecified value
ContinuityA4±GroundPassenger 's CourtesyOFFNo continuityygy
ONContinuity
A5±GroundIgnition KeyPull offNo continuitygy
Put inContinuity
A6±GroundDriver's CourtesyOFFNo continuityy
ONContinuity
A8±GroundSeat BeltUnfastenContinuity
FastenNo continuity
A10±GroundConstantContinuity
B1±GroundPassenger's DoorUnlockContinuityg
LockNo continuity
B2±GroundDriver's DoorUnlockContinuity
LockNo continuity
B3±GroundLight Control SwitchOFFNo continuityg
TAIL or HEADContinuity
B6±GroundLight Control SwitchTAIL or OFFNo continuityg
HEADContinuity
VoltageA1±GroundConstantVoltageg
A2±GroundConstant*Voltage
A7±GroundIgnition SwitchONVoltageg
LOCK or ACCNo voltage
A9±GroundIgnition SwitchONBattery voltageg
LOCK or ACCNo voltage
A11±GroundIgnition SwitchON or ACCVoltageg
LOCKNo voltage
* There is resistance because this circuit is grounded through the bulb.\
±
BODY ELECTRICAL SYSTEM Light SystemBE±49
WhereEverybodyKnowsYourName

(Canada)
Check forTester connectionConditionSpecified value
ContinuityA4±GroundPassenger's CourtesyOFFNo continuityygy
ONContinuity
A5±GroundIgnition KeyPull offNo continuitygy
Put inContinuity
A6±GroundDriver's CourtesyOFFNo continuityy
ONContinuity
A8±GroundSeat BeltUnfastenContinuity
FastenNo continuity
A10±GroundConstantContinuity
A12±GroundConstantContinuity
B1±GroundPassenger's DoorUnlockContinuityg
LockNo continuity
B2±GroundParking Brake
Switch PositionOFF (Switch pin
pushed in)No continuity
ON (Switch pin re-
leased)Continuity
B3±GroundDriver's DoorUnlockContinuity
LockNo continuity
B7±GroundHeadlight Dimmer
Switch PositionLow Beam or High
BeamNo continuity
FlashContinuity
B8±GroundHeadlight DimmerLow BeamNo continuityg
Switch PositionHigh Beam or FlashContinuity
B10±GroundLight Control SwitchOFFNo continuityg
HEAD or TAILContinuity
B12±GroundConstantContinuity
B13±GroundLight Control SwitchOFF or TAILNo continuityg
HEADContinuity
VoltageA1±GroundConstantVoltageg
A2±GroundConstant*Voltage
A7±GroundIgnition SwitchONVoltageg
LOCK or ACCNo voltage
A9±GroundIgnition SwitchON*Voltageg
LOCK or ACCNo voltage
A11±GroundIgnition SwitchON or ACCVoltageg
LOCKNo voltage
B4±GroundEngineSTOPNo voltageg
RunningVoltage
B11±GroundConstantVoltage
* There is resistance because this circuit is grounded through the bulb.\
If the circuit is as specified, trying replacing the relay with a
new one.
If the circuit is not as specified, refer to BE±35 wiring diagram
and inspect the circuit connected to other parts.
BE±50
±
BODY ELECTRICAL SYSTEM Light System
WhereEverybodyKnowsYourName

DEFOGGER SYSTEM
Description
The component parts of this system and their functions are described in the\
following table.
 Parts Name\
 \
Function
 Defogger\
 \
When over current flows in the defogger circuit, the Defogger fuse break\
s the circuit to pro-
tect it against damage.
 


Defogger Relay\
 
\

\

This relay is supplied with current from terminal IG1 of ignition switch\
(Ignition switch
ON) and switches large current from the defogger.
 


A/C Control Panel
Assembly

Defogger Switch\
 
\

\

The defogger switch is built into the A/C Control Panel Assembly. This switch is
supplied with current from the relay and fuse HTR. Grounds current from \
the defogger
relay, turning the defogger relay ON.
 




Defogger

Rear Window
 Outer Mirror\
 
\


\

\

These defoggers generate heat when current is supplied from the defogger\
relay.
Parts Location
±
BODY ELECTRICAL SYSTEM Lighting SystemBE±51
WhereEverybodyKnowsYourName

(c) Turn the defogger switch ON and check that the test bulb andindicator light turn ON, then turn OFF after about 15 minutes.
If operation is not as specified, replace the air conditioner control
panel assembly.
(Defogger Relay)
INSPECTION OF DEFOGGER RELAY
INSPECT RELAY CONTINUITY AND OPERATION
If continuity is not as specified, replace the relay.
(Defogger Wires)
INSPECTION AND REPAIR OF
DEFOGGER WIRES
1. INSPECT DEFOGGER WIRESNOTICE:
w When cleaning the glass, use a soft, dry cloth, and wipe
the glass in the direction of the wire. Take care not to
damage the wires.
w Do not use detergents or glass cleaners with abrasive
ingredients.
w When measuring voltage, wind a piece of tin foil around
the top of the negative probe and press the foil against
the wire with your finger as shown.
(a) Turn the ignition switch ON.
(b) Turn the defogger switch ON.
(c) Inspect the voltage at the center of each heat wire as
shown.
 Voltage Criteria
Approx. 5 VOkay (No break in wire) Approx. 10 V or 0 V Broken wire
HINT: If there is approximately 10 volts, the wire is broken be-
tween the center of the wire and the positive (+) end. If there
is no voltage, the wire is broken between the center of the
wire and ground.
±
BODY ELECTRICAL SYSTEM Defogger SystemBE±53
WhereEverybodyKnowsYourName

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
WhereEverybodyKnowsYourName

(b) Remove the luggage compartment trim.
(c)Disconnect connector.
(d) Remove four nuts and rear combination light assembly.
2. INSTALL REAR COMBINATION LIGHT ASSEMBLY Follow the removal procedure in reverse to carry out installa-
tion.
(License Plate Light)
REPLACEMENT OF LICENSE PLATE
LIGHT
1. REMOVE LICENSE PLATE LIGHT(a) Disconnect negative (±) terminal from the battery.
CAUTION: Work must be started after. 20 seconds from
the time the ignition switch is turned to the ºLOCKº posi-
tion and negative (±) terminal cable is disconnected from
the battery.
(b) Remove the rear bumper.
(c) Disconnect connector.
(d) Remove three screws and the license plate light.
2. INSTALL LICENSE PLATE LIGHT
Follow the removal procedure in reverse to carry out
installation.
BE±56
±
BODY ELECTRICAL SYSTEM Lighting System
WhereEverybodyKnowsYourName

Parts Replacement ± Stoplights
(Rear Combination Light)
(See page BE±56 )
(High Mount Stop Light)
REPLACEMENT OF HIGH MOUNT STOP
LIGHT
1. REMOVE HIGH MOUNT STOP LIGHT
(a) Disconnect negative (±) terminal from the battery.
CAUTION: Work must be started after approx. 20 se-
conds or longer from the time the ignition switch is
turned to the ºLOCKº position and negative (±) terminal
cable is disconnected from the battery.
(w/o Rear Spoiler)
(b) Separate the woofer speaker cover from package tray
trim.
(c) Disconnect connector.
(d) Remove woofer speaker cover.
(e) Remove five screws and separate the high mount stop light from woofer speaker cover.
(w/ Rear Spoiler)
(f) Separate the rear spoiler from the luggage door. (See page BO±106 )
(g) Remove three screws and separate the high mount stop
light from rear spoiler.
2. INSTALL HIGH MOUNT STOP LIGHT For installation, follow the removal procedure in reverse.
Parts Inspection± Stop Light System
(Stop Light Switch)
STOP LIGHT SWITCH
REMOVAL AND INSTALLATION OF STOP
LIGHT SWITCH
1. REMOVE STOP LIGHT SWITCH
(a) Remove instrument panel subassembly cover underNo.1 and brake pedal return spring.
(b) Disconnect connector.
(c) Remove a nut and switch.
2. ADJUSTMENT OF STOP LIGHT SWITCH (See page BR±4)
3. INSTALL STOP LIGHT SWITCH For installation, follow the removal procedure in reverse.
±
BODY ELECTRICAL SYSTEM Lighting SystemBE±61
WhereEverybodyKnowsYourName

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
WhereEverybodyKnowsYourName

Parts Replacement (Turn Signals)
(Cornering Light)
REPLACEMENT OF CORNARING LIGHT
1. REMOVE CORNARING LIGHT(a) Disconnect negative (±) terminal from the battery.
CAUTION: Work must be started after approx. 20 se-
conds or longer from the time the ignition switch is
turned to the ºLOCKº position and negative (±) terminal
cable is disconnected from the battery.
(b) Remove front under cover. (See page BO±92 )
(c) Remove a screw and two nuts.
(d) Remove cornaring light from bumper.
(e) Disconnect connector.
2. INSTALL CORNARING LIGHT For installation follow the removal procedure in reverse.
(Front Turn Signal Light)
REPLACEMENT OF FRONT TURN
SIGNAL LIGHT
(See page BE±37 )
HINT: Replacement of Headlight (LO±Beam)
(Rear Combination Light)
(See page BE±56 )
±
BODY ELECTRICAL SYSTEM Lighting SystemBE±67
WhereEverybodyKnowsYourName

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
WhereEverybodyKnowsYourName