
OVERALL ELECTRICAL WIRING DIAGRAM
1234
11 LEXUS SC300
4ACC
IG1
ST1
AM1 2
1J
51C 6
1I
82
1J
7
1B
51C 1
1H
10
1B
4 1K
13 2
18 BT1 6Ba1
12 BT1 BT1 13 BT1 13 I F2 IF1 IF1 I F1
7B
GN D2
10 AUNSW
5AE1
4A ASW
16 A MSW
17 B
VC
11 A MRY
12 A M2
3A M1
8A ECUE
9A SO
1A SI
2A +
1B
IG 6B
P 18 A
BATT
IF IH 6BU1 47
68
3214
11
19 13 12 1B
2
1H
15
1C
8
1K
7
4B +B 2B
TEM+ 11 B
TEM±
10 B TIM+
6ATES
3B TIM±
7A TI S
M
M
10 1 5 6 3 4 1
WB
BR±B
B±R
R
L±W L±W R
GR
B±R
L±W L±Y L±B
R 6
5
BR 5W± L
W±L W
W
GR GR GR B±R
RR R
L±W
L±W
W
R± B
W± B
Y
B
W
BR±B
BR±B
R±WR±Y
R P
V±Y
V± W
B
W
BR±B
BR±B
P
R
R±Y
BR
P± L
R±L
R±B
Y±R
R±W
BR
L±Y
L±B
BR
W±B
60A MAIN
120A ALT 100A AM1F9
FUSE BLOCK 40A
IGSW
B±Y
GR B±R
BR±B
BR15A
ECU± I G 10A
DOME
Fr om A/ T Indicat or SW
< 3±6>
TI L T AND POWER TELESCOPI C ECU30A
POWER
30A
DOOR
TEL ESCO
LONG TILT
UP
TEL ESCO
SHORT TILT
DOWN
MANUAL SW AUTO SW
T I LT POSI TI ON
SENSOR
TI L T CONTROL MOTOR
TELESCOPIC POSITION
SENSOR
TE LE SCOP I C CONT ROL MOTOR No . 1
No . 2
SET
D1 2
DRIVING POSITION
MEMORY AND RETURN
SW
(
SHI ELDED )(
SHI ELEDED)
BATTERY
BR±B
T7
TELESCOPIC
POSI TI ON SENSOR
Power
Source Power Tilt and Power Telescopic
I15
IGNITION SW
6 74
To Unlock Warning SW
[IGNITION SW]< 4±4> < 5±4>
To Door Lock Mot or,
Door Unloc k Detec tion SW and
Door Open Detec tion SW LH< 17±4>
From Remote Cont rol Mirr or ECU
< 10±4> W
T10 A , T11 B
C17
TI LT AND POWER TELESCOPIC UNIT
[COMB. SW]
(
Cont . ne xt pa ge )
5
4
3
2
1
6789101112
12 34 56 78
9 10 1112 13 14 1516 1718
AA
T11 T10
TIL T AND POWER
TELESCOPI C ECU
W±L
Left kick panel Under t he ashtray LH2
1
3
4 1
2
To Parking Brake SW
< 21±2>
GR
( M/T )
(
A/T )
WhereEverybodyKnowsYourName

OVERALL ELECTRICAL WIRING DIAGRAM
1234
12 LEXUS SC300
2
1B
5
1F
9 2
1F
8
1I
15
6 237
2 1
4 11 1B
2
1D
91J 21I 7
10 8 9 5 1 4
11 IF2 3 IF2
11 IP1 3 IP1 2 IP1
M
12
M
12
1D
10 1J 1
1F
6
IF
51
42
3
W± B W±B
WW
W± L
Y
Y
5213
4
RR
L±W L±RL±Y
L±B
W±B
R
W±B G± Y
R±L
G±W
L
L
L
Y±R W± L
W
W±B R
G± Y
R
G±Y R± L
G± W
L G±W
R±L
W± B
W± B
10A
DOME
W± L W
1 2
R
60A MAIN
120A ALT
100A AM1
F9
FUSE BLOCK
D4
DAY/NI GHT
SHIFT SW INNER
MIRROR
M2
MOON ROOF CONTROL REL A Y
M3
MOON ROOF
CONTROL S W
POWER WI NDOW
RE LA YP5
POWER WINDOW MASTER SW AND
DOOR LOCK CONTROL SW LH
BATTERY
To Unlock Warning
SW<4±4><5±4>
From Theft Det err ent and
Door Lock ECU< 17±3>
P7
POWER WI NDOW
MOTOR RH
P6
POWER WI NDOW
MOTOR LH P4
POWER WI NDOW
CONTROL S W RHL
L 30A
POWER
POWER
MA I N RE LA Y
W±B
Power
Source Liquid Crystal
Inner Rear
View Mirror
Moon Roof Power Window
OP EN
CL OS E
UP
DOWN1
7 4589
8BZ1 7BZ1 6BZ1 2BZ1V
P
P±L
V± W NO. 2 NO. 1
M
4BZ1 5BZ1
B± Y
W± B
45
1326
B
6
BR
LG W
W± Y
B
W± B W± B
W±B
1BZ1 12
L
M4
MOON ROOF MOTOR
AND LIMIT SW
BZ13
L
R
WINDOW
LOCK 3 2
5 1
B
Left kick panel1
2
5
1F
R
WhereEverybodyKnowsYourName

1234
15 LEXUS SC300
4ACC
IG1
ST1
IG2
AM1
3
2
6
11 AM2
1J
7 1J
81J 51J 3
1B
4 1E
21E 17 1I9
1G
6 1G
10
3G
6 3A
5
7IG2 16 IJ26IJ2
16 IE1
4 9 14 13 1
6 42 3315 138453
2 4
7 8 3H
15
3A
1
12 IG1
1
2
IJ IF
4
1G
18
1E
13
1H 3
1G
1
IJ 1B
2
1G
11E 13
611
1211 10
11 10 12 9
1G
71G 9
3D
11
1E
31E 4
3A
3
3A
7
12
SPI RAL
CABLE
11
12
45 23 IK1
10 IK1 3B
2
3E
10
3E
33H 12
7
514
2
W
W± R
W±B
W±B
W±B
P±L
B±Y
B±O
L±R
L±R
L±R
B±R
B±R
L±R
B±O
W± R
W± R W± LB±O
B±Y
P±L
W± B P
LG±B
LG±R
W± B W± B R
W
GR B
YL
P± B
B±Y
B±Y
B±Y P±B
B±Y
P±B
B±Y P±B B± Y P± B
W± B W± B
V
P
LG±B
LG±R
G± W
V
W± B
W± B W
W±RW± L
W± L W± L W
W± R
40A
IGSW 15A
ECU± I G
15A
CI G
I15
IGNITION SW
100A AM1
120A ALT
30A AM2
30A INJ
SHI FT LOCK
SOLENOID
SHI FT LOCK
CONT ROL S W
F9
FUSE BLOCK S1 0
SHI FT LOCK ECU P2
PPS ECU
P1
PPS SOLENOI D
STP KLS+ E
E SPD SOL + SOL±
L±R
L G±RG
G±W
I15
KE Y I NTE RLOCK
SOLENOI D
[IGNITION SW]
Fr om Stop Light SW
<4±6><5±6>
From Combination
Meter< 21±5>
BATTERY E1 E2 +SL ±SL +SR ±SR D+ D± TC LA
+B
IG2
ACC
+B
IG
ACC
SLS+
SLS±
PT
P±
P2 7. 5A
IGN
15A
ECU± B
C12
AIRBAG
WARNING
LIGHT
[COMB. METER]
F1
FRONT AIRBAG
SENSOR LH F2
FRONT AI RBAG
SE NS OR RH
A29
AIRBAG SQUIB
T6
TDCL
(Total Diagnostic
Communicat ion Link )C3
CHECK CONNECTOR
TC AB TC AB
Power Source Shift Lock PPS SRS Airbag
C10
CENTER AIRBAG SENSOR ASSEMBLY
Right kick panel Left k ick panel
3
4
WhereEverybodyKnowsYourName

OVERALL ELECTRICAL WIRING DIAGRAM
1234
17 LEXUS SC300 (
Cont . ne xt pa ge )
4 ACC
IG1
ST1
AM1 3
2
1J
7 1B
21J 51J822
1B
51E 11
1E
51K 7 1K
13 1I 14 22
1H
10
1B
4
1
4 9IJ1 4IJ19IE1
8BY1 8 BT1 14 IE1 7 BT1 9 IP1 17 IG1 15 IF2 14 IF2 1 2
8A +B 2 2A
IG 7B
ACC 4B
SH 20 A
+B1 5B
HE AD 13 B
TAI L 1A
SRLY 11 B
HORN 8B
DS WP
10 B DS WL
12 B DSWH
1B LUG
5ATO
19 ATSW
6AKSW
14 AL1
10 AUL 3
3 1 2
1 1
2
2
1 1
BL BM EA IF 3F
7
3A
1
18
1E 10
1D
1
1J
16 A
E
15 AUL 1
18 A UL2
17 A LSWP
5IF2 4IF2 5IP1 14IP1 8IP1 19IP1 12 A
PCTY 7A
LSWP 4A
ACT+ 3A
ACT± 11 A
LSWD 13 A
DS WD
LOCK
UNLOCK
IJ
IF 20 IP12
31
1
3
2
LOCK
UNLOCK
1
2
8
LOCK
UNLOCK
1
3
2
LOCK
UNLOCK
G±W G± Y Y
R±B
W± L L±W L±R
P± B
R± W R
G±Y G±W
W±B
W±B
W± B
W± B
W± B G± Y
R± B G±L
W
R
R±Y
G±W L±O
G±R Y±R
R± W P± B
L±R
L±W
W± L R±B R
W
B±O
L±R
B±R
L±W L±W
W
W
W
R W
W± L
W
W± L
W± L
W
L±R
L±G
G±L
R±W
B
W±B
L
Y G±Y
G
R±B G±L
G±Y
G±W
G±W G± YG± L
R±B G± L
R±B G
G± Y
W±B
W± B W± B W± B
R
W±B
W±B
W± B
W± B W±B
R± L
B±Y
B±O
4 1
3 2
60A MAIN
100A AM1
120A ALT
40A
IGSW
F9
FUSE BL OCK I15
IGNITION SW
30A
DOOR
15A
ECU±
IG15A
CI G
25A
HAZ±HORN 10A
DOME
T1
THEFT DET ERRENT
HORN
THEFT DETERRENT AND DOOR LOCK ECU
F10
FUEL LID
OPENER SW
L±R
L±G
G± L
R± W
B
L
BATTERY
F14
FUEL LID OPENER
SOLENOID
L5
LUGGAGE COMPARTMENT
KEY UNLOCK SW E5
ENGI NE HOOD
COURTE SY SW
To Luggage Compartment
Light SW< 6±3> L4
LUGGAGE COMPARTMENT
DOOR OPENER MOT OR
L1
LUGGAGE COMPARTMENT
DOOR OPENER SW
To UNLOCK WARNING SW
<4±4><5±4>D7
DOORKEYLOCKAND
UNLOCK SW LH
P5
DOOR LOCK CONT ROL S W LH
[ POWER WI NDOW MASTER SW] Fr om Headlight Relay
<4±2><5±3>
From Taillight Relay
<4±3><5±3>
Fr om Sterter Relay
<1±3><2±2>
Fr om Hor n Rel ay
< 13±1>
To Power Main Relay
< 12±4>
D9
DOOR LOCK CONT RL
SW RH
D8
DOORKEYLOCKAND
UNLOCK SW RH
Power
Source Theft Deterrent and Door Lock Control
W± L
B±YR± L
6 2
7 T8 B , T9 A
Fr om Tilt and Power
Telesc opic ECU< 11±1>
Y
Under the center
pillar RH Ba ck
panel
centerFro nt si d e of
right fender
Lef t kic k panel
Left k ick panel Right k ick
panel
R± B
M6
5
5
6
2IG19A
To Trip SW and
Theft Deterr ent
I ndic ator Light
< 21±4>
G± B G± BIND
WhereEverybodyKnowsYourName

OVERALL ELECTRICAL WIRING DIAGRAM
1234
21 LEXUS SC300 (
Cont . ne xt pa ge )
4 ACC
IG1
ST 1
IG2
AM1
3
2
6
11 AM2
1J
7
1B
4 16 IE1
20 IK110 IK2
1IE1
1J
31J 51J821B 2
1E
1E
18
1E 1H1E 2 1E
131B
IG1 20 3D
3A 4
3D
2
3C
6
3A
2
3F
1 2 1 6
3F 5
3C
5
3A
IK16
IK1 7
10 IJ1
IE110
IG118
EB
19 IG1
ED EA 13 IE2 14 IG3 W± R
R
Y
B± O Y± B
V±R V± Y
R± W
L±R
W
R±Y B
V±W V
R
L±R
P± L
R
L±R L±R
P± L
P± L
Y
B±O B±YP±L
W± L
R± W
B
W± B R±W
B
W
W
W±L
W± L W±L
W
W±R
Y±B
V±R
V± Y
R±WV±Y V± R Y±B
W± R
W
W± R
B± O
R±W R± W
B
B
R±W R±W
R±W V±Y
BR
W± B
R±W Y
W±B Y
R4713
21 11
4
12
8
7
9
2
1
2
340A IGSW
100A AM1
120A ALT
60A MAIN
30A INJ
30A AM2
14
9 I15
IGNITION SW
7. 5A I GN
10A GAUGE
15A CIG
10A DOME
15A ECU±B
From ABS ECU
<9±2>
From ABS ECU
< 8±5>
(
* 1 )
(
* 2)
6
BATTERY
F9
FUSE BLOCK
12
O2
OI L P RE SS URE SW
C5
COOLANT LEUEL
WARNING SW E6
ENGI NE OI L L EVEL
WARNING SW
P3
PARKI NG
BRAKE SWD2
DIODE
(f or Par king
Brake )
B1
BRAKE FLUID
LEVEL SW
B
B
R±W R±WR±W
R±W
B
B B
( Canada )
(
Canada )
( US A )
(USA )
(
US A )
(
US A )
(
Canada )
(
Canada )(
Canada )
(
* 2
) (
* 1)
(
US A )(
US A)
(
USA )
R±W
R± W
Fro m Dayt i me
Running Light
Relay< 4±4>
Fr om Cr uise Control
ECU< 16±2> T1 5
TRIP SW AND THEFT DETERRENT
I NDI CA TOR L I GHT
S3
SPEED SENSOR No. 1
From Tr act ion ECU
<8±7>
2
W
12 12 2 54 11 13 *
1: (
w/ Tr action Contr ol )
* 2: (
w/oTractionControl )
Power
Source Combination Meter
R±WL±R
R
4 3
SECURITY
M
H
SET
RESET A/ B
W1
WASHER
LEVEL SW
P± L
L±R
R W± R
From ABS ECU
<8±5>
( * 1)
R
R
10 11 12 13 17 18 19 20 21 12345 6789
14 15 16 12 34 56 78
9 10 1112 13 14 1516 1718
17 18
1 2345 6789 10
23
22
21
20
19
15
14
13
12
11 16
AB C
C12 C13 C14 COMBINATION METER
1 1
23
DE
FUEL SENDER
F1 7 F1 8
Rear side of
c ylinder head LH Fr ont side of
right fender Fr ont s ide of
left f ender
2
1
2 2
1 1
1
B
S HORT CONNE CTOR
1
2 12F
S23
G
S22
7BU1
From Tilt and
Power Telesc opic
ECU< 11±2>
GR
B
( M/T ) 3
G±B
From Theft Det err ent and
Door Lock ECU< 17±2>
WhereEverybodyKnowsYourName

567 8
21 LEXUS SC300(
Cont ' d )
AIR BAG
CHA RGE
OIL
OIL LEVEL COOLANT
LEVEL REAR
LI GHT
PWR
ABS TRAC
TRAC OFF
CRUISE WASHER
O/ D OFF
FUEL
SEAT BELTP
R N D 2 L
A
C
C A
A
B
B
B
C
C
C
C
C
C
C
B C
C
B
B
BA
B
A
A
C
CA A A A A A A A
C
C
C
C C C A C C B B B B
B A A C C
10 : 00
BK 1E
18 3D
10
3A
1
1J
1 1K
12
IH IF ED
IK1
8
IK2 IK1
9
1
E
3
E
2
E
1
D
BU110
BU1
3
BU1
4 11
11
1
14
19
8
18
11
13 6
18
17
16
20
19
15
13
3
15 5
1
20 9
18 8
11
87 1 2 3 4 5 16 17
2
3
4
5 10 9
12 23 12 4 17 16 7
6
15
10 22 21
W± R
RY
B±O
Y±B
V± R
V±Y
R±W
L±R
W
R± Y B
V±W V
R
L±R
P±L
Y±B
B±Y
B± W
W±B BR
B
W± B W± B BR±B
Y± G
B
Y±G
BR±B
W± B
W±B
W±B
BR±B W± B BR
Y±G
WATER
TEMP.HI GH BEAM TURN
LH
RH
BRAKE DOOR
TACHO
TRI P
SPEED
ILLUMINATIONCHECK±
ENGINE
FUEL
See Taillight and
St op Light Sy stem
<4±6><5±6>
SeeEngineControlSystem
<2±3>
Se e ABS Sy st e m< 8± 7> < 9± 3>
See Cruise Control System
< 16±3>Se e ABS an d Tr act io n
Control System< 8±7>
SeeECTandA/TIndicator
System< 3±5>
D
F1 7 , F18 E
FUEL SENDER Y±B
B±Y
B±W 24
See SRS Airbag System< 15±4>
See Charging Sy stem< 1±2>
See Headlight Sys tem< 4±1> < 5±1>
See Turn Signal and
Hazard Warning
Light Sy stem< 7±3>
See ECT System< 3±5>
From Neutr al St art SW< 1±3>
See Interier Light System< 6±3> From Igniter º TACº < 1±5>
To Engine and ECT ECU< 2±7>
To Cruise Control ECU< 16±3>
To PPS ECU< 15±2> See Illumination System
<4±7><5±7>
See ECT and A/T Indic ator
Syst em< 3±6>
See Unlock and Seat Belt
Warning Syst em< 4±4> < 5±4>
W3
WATER TEMP.
SENDER
Combination Meter
1
COMBINATION METER C12 , C13 , C14
A
AB IG1
8
Under the
c ent er
pillar LH Under the
as htr ay LH
Lef t
kick panelRear side of
c ylinder head RH
C
2
G 2
F
1
F 14
L±R
P
P
SH OR T C ON NE CT OR
S2 2 G , S23 F L±R
WhereEverybodyKnowsYourName

244
Rear Window Defogger
and Mirror Heater
Remote Control Mirror
Seat Heater
Shift Lock
SRS AIRBAG
Starting
Taillight and
Stop Light
Theft Deterrent and
Door Lock Control
Turn Signal and Hazard
Warning Light
Wiper and Washer
Wireless Door Lock
Remote Control
Horn
Ignition
Illumination
Interior Light
Liquid Crystal Inner
Rear View Mirror
Moon Roof
Power Seat
(Driver's)
Power Source
Power Window
PPS (Progressive
Power Steering
Radio and Player
ABS and
Traction Control
Automatic
Air Conditioner
Auto Antenna
Back±Up Light
Cellular Mobile
Telephone
Charging
Cigarette Lighter
Combination Meter
Cruise Control
Headlight and Light Auto
Turn Off (for USA)
Headlight
(for Canada) ECT and
A/T Indicator
4±2 16±2 7±2
3±2 21±2 3±8
14±4
18±2 19±4 (w/o CD Player)
20±8 (w/ CD Player)9±2 8±2
4±7 (for USA)
5±7 (for Canada)11±2
12±311±5 (w/ Driving
Position Memory)11±7 12±1 1±5 13±2
6±2 15±2 14±2
13±2
17±7 7±3 17±2 15±3
1±315±2
Power Tilt and
Power Telescopic12±2
Power Seat (Passengerºs
and Electric Tension Header
5±2 2±2
Cornering Light ABS (Anti±Lock
Brake System)
22±2
Engine Control Unlock and Seat
Belt Warning
1±2
23±2 (w/o Driving
Position Memory)
1 23±119±2 (w/o CD Player
20±2 (w/ CD Player
14±310±2 (w/ Memory)
5±7 (w/o Memory)
4±3 (for USA)
5±3 (for Canada) 4±5 (for USA)
5±5 (for Canada)
OVERALL ELECTRICAL WIRING DIAGRAM
WhereEverybodyKnowsYourName
![LEXUS SC400 1991 Service Repair Manual
47
216182
216
178
216
129 104 144 10260
90
216 62
68
11 2
148
104
111 200 148 148 190
D1
C16 C24
C15 C19 C23 C22
C12
C13
C14C14
C13
C12
Airbag W arning Light
Charge Warning Light
Dimmer SW [Comb. SW] LEXUS SC400 1991 Service Repair Manual
47
216182
216
178
216
129 104 144 10260
90
216 62
68
11 2
148
104
111 200 148 148 190
D1
C16 C24
C15 C19 C23 C22
C12
C13
C14C14
C13
C12
Airbag W arning Light
Charge Warning Light
Dimmer SW [Comb. SW]](/manual-img/36/57051/w960_57051-3993.png)
47
216182
216
178
216
129 104 144 10260
90
216 62
68
11 2
148
104
111 200 148 148 190
D1
C16 C24
C15 C19 C23 C22
C12
C13
C14C14
C13
C12
Airbag W arning Light
Charge Warning Light
Dimmer SW [Comb. SW]Cruise Control Indicator Light
[Comb. Meter]A/T Indicator Light
[Comb. Meter]
Combination Meter
Rear Lights Warning Light Turn Signal Indicator Light
[Comb. Meter] High Beam Indicator Light
[Comb. Meter]
Check Engine Warning Light
Open Door Warning Light
Traction Indicator Light
ABS Warning Light
[Comb. Meter] Seat Belt Warning LightABS Warning Light and T raction
Off Indicator Light [Comb. Meter]
Coolant Level Warning LightCruise Control ECU Turn Signal SW
[Comb. SW]
Wiper and Washer SW
[Comb. SW]
Choke Coil
Crutch Start SW
Cruise Control Clutch SW
Diode (for Brake Fluid Level)Light Control SW
[Comb. SW] Horn SW [Comb. SW]Combination MeterCornering Light SW
[Comb. SW]
C12 80
82
216
216 216 98
86
216134
216
216 216 184
216
80
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102 80
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(4)
: R/B No. 5 (See page ) 22
WhereEverybodyKnowsYourName