LEXUS SC400 1991 Service Repair Manual

INSPECTION OF MIRROR DEFOGGER
INSPECT MIRROR DEFOGGER
(a) Connect the positive (+) lead from the battery to terminal 7 (4)
and the negative (±) lead to terminal 8 (5).
(b) Check that the mirror becomes warm. HINT: It will take a short time for the mirror to become warm.
If the mirror does not become warm, replace the mirror as-
sembly.
( ): w/o Driving Position Memory
Troubleshooting
You will find the cause of trouble more easily using the table shown belo\
w. In this table, the number indicate
the order priority of the causes in trouble. Check each part in the order s\
hown. If necessary, replace the parts.

Refer to 1992 LEXUS SC300 Repair Manual (Pub. No. RM260U2)
See pageBE±4 , 20
BE±4 , 20
BE±4 , 22
BE±172
BE±173
BE±173
BE±174
±
BODY ELECTRICAL SYSTEM Defogger SystemBE±55
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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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WIRING AND CONNECTOR DIAGRAMS ±
Taillight System
BE±54±
BODY ELECTRICAL SYSTEM Lighting System
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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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(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 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
WhereEverybodyKnowsYourName

(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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WIRING AND CONNECTOR DIAGRAMS ±
STOP LIGHT SYSTEM
BE±60±
BODY ELECTRICAL SYSTEM Lighting System
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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
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