
OVERALL ELECTRICAL WIRING DIAGRAM
1234
3 LEXUS SC300 (
Cont . ne xt pa ge )
4 ACC
IG1
ST1
IG2
AM1 2
6
11 AM2
1J
7 21J
3
2
2
1B
4
2221I
5
EB1 EB2 4 EB1 11 IJ2 3 IJ2
16 IE1
9BS2
B
S1
B
OD1
8BS3
80 BEO1
79 BEO2
42 BVTA2
63 BIDL2
23 BSP2
3BSP2±
69 BE1
4BE11
24 A
M±REL 32 A
+B 1 31 A
+B 33 A
BATT 76 B
NSW
1A
IGSW 2A
SP1 41 B
VC 43 B
VT A1 65 B
E2 64 B
IDL1 44 B
THW 26 B
G1 25 B
G2 6B
G± 5B
NE 10 A
L 9A
2
4 3
4 2
123 SeeEngineControl
Sy stem< 2±8>
See Engine Contr ol
Syst em< 2±6>
W±R W± R B±Y
W± L
W
B±OW
B±O
B± O
B±R
B±R
B±R
B±O
B±Y
B±O PP B±OB±Y
BR±Y
W± RR± L
EB EE EE 1218 A
P 28 A
OD2 12 A
OD1
17 A TT
29 B VF1
20 A TE1
28 B VF 2
21 IK1 22 IK1
3 4
See Engine Contr ol Sy stem< 2±5>
W
G
G± O Y
GR ±R
W±B
W±B
W±B
BR
BR W± B
W± B
P
V BR
BR
WG
G±O
GR±R BR± Y W± B
G±O G±O Y G± O
W
B±Y
I15
IGNITION SW
W± R W W
60A MAIN
100A AM1
120A ALT
30A AM2
30A INJ
F9
FUSE BLOCK
40A IGSW
EF I
MAIN
RE LA Y
30A
EFI
7. 5A
IGN
3 1
83B±RE1
ECT SOLENOID
NO. 1 NO. 2
NO. 3
S4
SPEED SENSOR
NO. 2 (
for ECT ) E8
ECT
PATTERN
SELECT SW
From Combination
Meter< 21±4>
To Cruise Cont rol ECU
< 16±3>
See Engine Contr ol Sy stem
< 2±7>
B± Y
ENGI NE AND ECT ECU
Power
Source ECT and A/T Indicator
BATTERY
7 4 91413
6
POWER
NORMAL
A
19 TE2
E9 , E10
BA ENGI NE AND ECT ECU
ENGINE AND ECT ECU
Fr ont s ide of
left fender Rear side of
c ylinder head LH Rear s ide of
cy linder head LH
3
1
To Cruise Control
ECU< 16±3>
See Engine Control
Sy st e m< 2 ±8 > LG
Y B
W12 10 10
30
50
70
1
21
41
61 2
22
42
62 3
23
43
63 4
24
44
64 5
25
45
65 6
26
46
66 7
27
47
67 8
28
48
68 9
29
49
69 11
31
51
71 20
40
60
80
19
39
59
79
18
38
58
78
17
37
57
77
16
36
56
76
15
35
55
75
14
34
54
74
13
33
53
73
12
32
52
72
1020
30
40
1
11
21
31 2
12
22
32 3
13
23
33 4
14
24
34 5
15
25
35 6
16
26
36 7
17
27
37 8
18
28
38 9
19
29
39
A
E1 0 DARK GRAY
B
E 9 DARK GRAY
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567 8
4LEXUSSC300(
Cont ' d )
1
2
1
2 1D
11 E 1I
10
3G
1
1B
2
3A
9
1C
10
1E
20
1H
1
9BU1
1Bd15IG7
11 Bc 1
Be1 2 1
1
2
3A
10
1 2
3 84
921117
3G
83A 2
3A
1
2
12
1
1
4
1
2 1
2
EA BM BL 2Bd14
1
3
8
2 10
3H
3
3C
3
3F
2
3G
5
3H
1
3F 6
1
2
1
3
2
2
9
5
1
10
F 5
G
IQ1
2
6
7 IQ1
4
12
3A 9
3E 6
3E 6
3E
6
3H 2
3H 1
3H 1
2
10 11 1 2
GW±G
G
G
GW±G W± GW±G
GW±G
G±O
G±O
G±O
G±O
G±O W±G W± G W± G
W± G W± G
W± G
G± W
W± BY Y
G±O
G
G
W± L
G
G
G
GW±BW± B W± B W± B
G
Y
V± G
V± G Y
G±W
G± W
W±B
GGGG
G
W
G± W
G± W
B
W± B R± W
B
G±W G±W G±O
G±O
W± B W
W±GBR
Y± V L±B L
W±B
W± B
W± B
W±B
W±B
G
G
W± G W± G
W±B
±PK ±STP E HS +STP
ETCRLRVREILL±
7
G± O
G± O
+PK BWRN
T
15A
STOP
F3
LH
F4
RH
FRONT
CLEARANCE LI GHT
L3
LI GHT FAILURE SENSOR
RE AR LI GHT WARNI NG
LI GHT[ COMB. MET ER]
S12
STOP LIGHT SW
To ABS ECU<8±3><9±4>
To Shif t Lock ECU< 15±2>
G2
GLOVE BOX
LI GHT SW
F5
LH
F6
RH
FRONT SIDE
MARKER LIGHT
L2
LI CE NCE
PLATE LIGHT
W± B W±B
W±BH9
HIGH MOUNT
STOP LIGHT
H8
HIGH MOUNT
STOP LIGHT A1
A/C CONTROL
ASSEMBLY
A15
A / C C ON TR OL SW
AND RADIO SW
RADIO AND PLAYER
( w/o CD Player )
R4
RADIO AND PLAYER
( w/ CD Player )
T1 2
TRACTION CUT SW AND
SEAT HEATER SW
C1 1
CIGARETTE LIGHTER
A21
A/T INDICATOR LIGHT E8
ECT PATTERN
SELECT SW
T1 5
TRIP SW AND THEFT DETERRENT
INDICATOR LI GHT
R9
RHEOSTAT
G1
GLOVE BOX
55
13 13W±B
W±B
W± B W± B W± B
R± W
G±R
R± W G±R G±RTAI L AND
STOP LIGHT
[REAR COMB.
LIGHT]
R1 0
LH
R1 1
RH
TAIL
ST OP
TAIL
ST OP
To Engine and ECT ECU< 2±3>
To Traction ECU< 8±8>
To Cr uise Control ECU< 16±4>
To Cruise c ont rol
ECU< 16±4>
To Po wer Se at E CU
(Driver' s )
< 11±5>
G± W
G±W
(
* 1 )
(
* 2 )
( * 2 )
(
* 1
)
C13 , C14
ED
H
H
H
H
I3C
1
17
2345
COMBINATI ON METER C12 , C14 IH R5 , R6
FG
12 34
5678910
12
3456
RADIO AND PLAYER
(
w/ o CD Pl ay er )
Taillight and Stop Light (
for USA )
Illumination(
for USA )
*2:
(
w/o Rear Spoiler )
*
1: (
w/ Rear Spoiler )
W
G±W
G± O
Fro nt s i de of
right fender Under t he
c ent er pillar RH
Back panel c ent er 23
G
W± G
H7
HA ZA RD SW
10 11 12 13 17 18 19 20 21
12345 6789
14 15 16
17 18
1 2345 6789 10
23
22
21
20
19
15
14
13
12
11 16 C1 2 I
C1 4 H
COMBI NATI ON METER
RE AR LI GHT WARNI NG
LI GHT[ COMB. MET ER]
WhereEverybodyKnowsYourName

OVERALL ELECTRICAL WIRING DIAGRAM
1234
16 LEXUS SC300
4ACC
IG1
ST1
IG2
AM1 2
1
11 AM2
3A
4
1J
7
1B
5 1J
5
2
1J
5
3C
4
1B
4 1E
12 1K 13 2 1K 4
3E
13A 8
3D
13 1H 10
16 IE1
15 IG1
10 IK1 2IJ2 1IJ2 9IJ2 7IG2
4 3
2 IE2 6 IE2 1 IE2 5 IE2 11 IE2 10 I E2 MEA
IG
1A
C14 A 3F
43E 3
Y
Y
B±R R
W± R R
BR±Y
P
W
G±W
Y± B
P± B R±W
R±LL
W±B
R±B
LG±R P
LG
G±R B±W
Y± B
Y±B
P±B
P±B
R± B
LG±R P
LG
G± R W±R W±R
W
R
W± R R
BR±Y
P
W± L
W W
W±B
W±B
W±B R±L R±L B±W
16
1
20
9
23
22
3
15 10
13
10 4 1115 5
6
1
3 4 18 13 24 25 26 12 11
675
123 MC
MO
VR3
VR2
VR1
GN D
CCS
CMS
PKB
TC
PI
100A AM1
120A ALT
60A MAIN
30A AM2 30A INJ
B BAT T N&C ECT I DL OD SPD STP+ STP± LY±B
3H
12
B
(
US A )
( CANADA )
6
W
4
W± R
BATTERY CRUI SE CONT ROL
INDICATOR LI GHT
[COMB. METER]
T6
TDCL
(Tot al Diagnos tic
Communic ation Link )C3
CHECK
CONNECTOR
F9
FUSE BLOCK
C15
CRUISE
CONTROL SW
[ COMB. SW]CA NCEL
RE SUME/
ACCEL SET/
COAST
MA I N
C8
CRUISE CONTROL ACTUATOR
POTENTIO METER
MAGNETI C
CLUTCH
C1 9
CRUI SE CONT ROL E CU
S12
STOP LIGHT SW From Stop Light SW
<4±6><5±6> Fr om º STOPº Fus e
<4±6><5±6> Fr om Combination Meter
< 21±5>
Fr om Engine and ECT ECU
<3±4> 10A GAUGE
15A ECU±IG 10A DOME 7. 5A ST
B±WB±Y W
40A IGSW
Cruise Control
14
5
47
14
9
Power
Source
C1 2 B , C14 A
TC
A/ D TC
To Parking Brake SW
< 21±2>
13 IG1
P± B
P±B
To Engine and ECT ECU
<3±3> Fr om Engine and ECT ECU
<3±2>8
I15
IGNITION SW
Ins trument panel
br ace LHFront side of
r ight fender
2
1
CRUISE CONTROL INDICATOR
LIGHT[ COMB. METER] 20 B
C12 B VR1 VR2 VR3 MC L
MO
GND
1221
IJ16
IJZ10
B±W
B±W B
B±W B±W
B±W
B±W
B±W
2
(
M/T )
( A/T )
C2 3
CL UTCH
START SW
C24
CRUISE CONTROL
CLUTCH SW
( M/T )
( A/T )
10 11 12 13 17 18 19 20 21 12345 6789
14 15 16
17 18
1 2345 6789 10
23
22
21
20
19
15
14
13
12
11 16
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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
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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
90
102 80
90
102
68
94
134
148
216
(4)
: R/B No. 5 (See page ) 22
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56
POWER SOURCE
AM2 AM1
ACC
IG 1
IG 2
321 6 411
ST1
1B
2
1J 5
1J 6
1J 3
1J 8 1K
13
1K 4
1J
4
1B
4
1J
7 I24
I33
I11 P
N 2
3
IE1
16
IJ16
3421314 59 7
116
W
WB
B
B
B±R
B±W B±W
W±L
B
B±O P±L B
B
B
W±L R
W±R
W±R
B
W±R Y
W±L
W±R
W
W±R
B±Y
B±W P±L
B±O
B±W
B±W
B±W
B±WW
B±R
15A ECU±B
15A STOP
30A POWER
30A DOOR
TAILLIGHT
RELAY 15A TAIL
7. 5A PANEL BATTERY
15A ECU±IG
7. 5A ENGINE
20A W IPER
10A GAUGE 20A TURN
10A HEATER
7. 5A ST
7. 5A IGN 15A CIG
7. 5A RADIO NO. 2
40A
IGSW
NEUTRAL
START SW
TO ENGINE AND ECT ECUTO CRUISE CONTROL ECU
TO ABS ACTUATOR RELAY,
ABS MOTOR RELAY AND
TRACTION BRAKE
ACTUATOR RELAYTO ALTERNATOR º Bº
IGNITION SW
FUSE BLOCK
TO TRACTION MOTOR RELAY100A AM1
60A ABS NO. 1
30A INJ
120A ALT 30A AM2
30A ABS NO. 2 60A MAIN
F9
N1
I15
5
1 3
2
2
6
3 4 1
5
1 2IJ2
8 B
B±W
B
B
(
M/T )
(
M/T )
C23
CLUTCH START SW
(
A/T )
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