warning light LEXUS SC400 1991 Service Owner's Guide

OKNG
NGOK
INSPECTION PROCEDURE
1Check operation of open door warning light.
Check that open door warning light comes on when each door is opened, and goes\
off when all doors
are closed.C
Check open door warning light circuit (See page
BE±118 ).
2Check voltage between terminal DSWD of ECU connector and body ground.
C
OK
P1. Remove the rear seat and RH quarter trim panel.
2. Remove the ECU.
3. Wireless door lock main switch on.
Measure voltage between terminal DSWD of ECU con-
nector and body ground, when all doors are closed.
Voltage: 10 ± 14 V
Proceed to next circuit inspection shown on matrix chart
(See page BE±454).
Check and repair harness and connector between ECU and door open detecti\
on switch.
±
BODY ELECTRICAL SYSTEM Wireless Door Lock Control SystemBE±471
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PREPARATION
SST (SPECIAL SERVICE TOOLS)
IllustrationPart No.Part NameNote
09213±31021
Crankshaft Pulley
Puller
For removing steering wheel
RECOMMENDED TOOLS
IllustrationPart No.Part NameNote
09082±00015TOYOTA
Electrical Tester
09041±0030Torx Driver
T30
For removing and installing steering wheel pad and
power window motor
09042±00010Torx Socket
T30For removing and installing steering wheel pad and
power window motor
EQUIPMENT
Part NameNote
Voltmeter
Ammeter
Ohmmeter
Test lead
ThermometerWater temperature sender gauge, Engine oil level, Warning switch, Seat heater
SyphonBrake fluid level warning switch
Oil bathEngine oil level warning switch
Bulb (1.4 W)Coolant level warning ECU
Bulb (3.4 W)Fuel sender, gauge, Seat belt warning relay
Bulb (21 W)Turn signal flasher relay
Dry cell batteryFuel sender gauge
Heat lightSeat heater
Hexagon wrench (6 mm)Power seat
BE±8±
BODY ELECTRICAL SYSTEM Preparation
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Description
The power source supplies power to each of the vehicle's electrical devices. It is composed of the battery, fuses
and relays, which are located centrally at relay block No. 2 and relay block No. 6 i\
n the engine compartment
and junction block No. 1 relay block No. 4 and relay block No. 5 in the \
cabin near the driver's feet.
Related systems for each Fuse
No.Part NameRelated Systems or Parts
1IGN
Charging System
AIR±BAG System1IGN
Engine
2ST
Starter
3WIPER
Wiper and Washer System
4HTR
Defogger System
A/C System
5ENGINE
Charging System
6RADIO NO. 2
Audio System
Power Mirror System

Cigarette Lighter
A/C System
7CIG
Combination Meter System
AIR±BAG System7CIG
Shift Lock System
Theft Deterrent System

TEL System
8STOP
Stop Light System
Cruise Control System
9TURN
Turn Signal and Hazard
Warning Light System
Cornnering Light System
10MIR HTR
Mirror Heater System
11PANEL
Illumination Light System
12ECU±B
Combination Meter System
AIR±BAG System

Combination Meter System
ECT System
13GAUGE
Back±Up Light
Transmission Indicator

Light Failare Sensor
ABS and TRAC

Power Seat System
Door Lock Control System

TEL System
Shift Lock System
14ECU±IG
Radiator Fan
Auto Antenna

Electric Tension Reducer System
Power Steering

Auto±Tilt away Steering
Cruise Control System
15TAIL
Taillight System
Side Marker15TAIL
Clearance Light
16DOOR
Power Seat System
Luggage Door Opener16DOOR
Door Lock Control System
Fuel Lid Opener System
17IG SWUpstream of ECU±IG, ENGINE, WIP, HTR, TURN, GAUGE, and ST Fuse
18PWR
Power Window System
Sliding Roof System
19ABS NO. 1
ABS and TRAC
20AM1Upstream of MIR HTR, TAIL, PANEL, STOP, ECUA±B, DOOR and PWR Fuse
21ALTUpstream of DEF, HTR, AM1, and ABS No. 1 Fuse
BE±18±
BODY ELECTRICAL SYSTEM Power Source
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No.Part NameRelated Systems or Parts
22MAIN
Upstream of ALT±S and EFI Fuse
23AM2
Charging System
Engine23AM2
AIR±BAG System
24ABS NO. 2
ABS and TRAC
25INJ
Charging System
Engine25INJ
AIR±BAG System
26DEF
Defogger System

Power Seat System
Sliding Roof System

A/C System
Liquid Crystal Inner Mirror System
27DOME
Combination Meter System
Interior Light System27DOME
ABS and TRAC
Wireless Door Lock Control System

Cruise Control System
Auto±Tilt away Steering

Theft Deterrent System
28EFI
Engine
29HAZ HORN
Turn Signal and Hazard Warning Light System29HAZ±HORN
Horn System
30RADIO NO. 1
Audio System
31TEL
TEL System
32ALT±S
Charging System
33TRAC
ABS and TRAC
34HEAD (RH±LWR)
Headlight System
35HEAD (LH±LWR)
Headlight System
36HEAD (RH±UPR)
Headlight System
37HEAD (LH±UPR)
Headlight System
38HTR
Blow Motor
±
BODY ELECTRICAL SYSTEM Power SourceBE±19
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5. USAINSPECT COMBINATION SWITCH CIRCUIT
(a) Pull the spool body to forward and separate spool bodyfrom steering column.
(b) C onnect the wire harness side connector to the
combination switch and inspect wire harness side
connector from the back side as shown.
(Light Control Switch Circuit)
Check forTester connectionConditionSpecified value
ContinuityB4±GroundConstantContinuity
(Dimmer Switch Circuit)
Check forTester connectionConditionSpecified value
*1B7 GroundLight Control Switch PositionOFF or TAILNo voltage*1B7±GroundLight Control Switch PositionHEADBattery voltage
VoltageLow beamNo voltage
*1B9±GroundDimmer Switch PositionFlash or High
beamBattery voltage
ContinuityB18±GroundConstantContinuity
*1: USA
(Turn Signal Switch Circuit)
Check forTester connectionConditionSpecified value
VoltageA3±GroundHazard Warning Switch ONBattery voltage
e 0 V
Ignition Switch ON and turn
signal switch positionRightBattery voltage
e 0 V
A4±GroundHazard Warning Switch ONBattery voltage
e 0 V
Ignition Switch ON and turn
signal switch positionLeftBattery voltage
e 0 V
ContinuityA12±GroundConstantContinuity
(Cornaring Light Control Switch Circuit)
Check forTester connectionConditionSpecified value
VoltageA8±GroundLight control switch HEAD andLOBattery voltagegg
dimmer switch positionHI or FLASHNo voltage
ContinuityA10±GroundConstant*2 Continuityy
A11±GroundConstant*2Continuity
*2 There is resistance because this circuit is grounded through the bulb.
If the circuit is not as specified, refer to BE±34 wiring diagram
and inspect the circuits connected to other parts.
±
BODY ELECTRICAL SYSTEM Lighting SystemBE±47
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(TAILLIGHT SYSTEM)
Description ± Taillight System
The component parts of this system and their function are as shown in the f\
ollowing table.
 Parts Name\
 \
Function
 


Light Control Switch\
 
\

\

Grounds current from the taillight control relay via the integration rel\
ay, switching each relay
and supplying current to the appropriate bulbs accordance with the switc\
h position.
 Taillight Control Relay\
 \
Turned on by signals from the light control switch and supplies current t\
o each bulb.
 




Integration Relay
\
 
\


\

\

Carries out ºLight Auto Turn±Offº of the headlights, fog lights and taillights and cuts off cur-
rent to the light control switch in accordance with signals from the GAU\
GE fuse and door
courtesy switch.
 


Light Failure Sensor\
 
\

\

This sensor senses when a bulb in rear combination light is burnt out an\
d lights up a warning
light.
Integration Relay\
 Integration Relay
(Daytime Running
\
 \

Refer to
BE±30. (y g
Light Relay: CANADA)\
 \

PARTS LOCATION ± Taillight System
±
BODY ELECTRICAL SYSTEM Lighting SystemBE±53
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(STOP LIGHT SYSTEM)
DESCRIPTION ± Stoplight System
The component parts of this system and their function are as shown in the f\
ollowing table.
 Parts Name\
 \
Function
 

Stop Light Switch
\
 
\

\

Creates a closed circuit for current from the STOP fuse when the brake pedal is depressed,
thus turning on the stop lights.
 


Light Failure Sen-
sor\
 
\

\

This sensor senses when a bulb in rear combination light is burnt out an\
d lights up a warning
light.
PARTS LOCATION ± Stoplight System
±
BODY ELECTRICAL SYSTEM Lighting SystemBE±59
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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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WIRING AND CONNECTOR DIAGRAMS
Turn Signal and Hazard Warning Lights
BE±66±
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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
±
BODY ELECTRICAL SYSTEM Lighting System
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