ignition LEXUS SC300 1991 Service Repair Manual

109
WITH THE IGNITION SW TURNED ON, THE CURRENT FLOWS TO TERMINAL 7 OF THE INTEGRATION RELAY THROUGH GAUGE
FUSE. VOLTAGE IS APPLIED AT ALL TIMES TO TERMINAL (A)4 (USA), (B)11 (CANADA) OF THE INTEGRATION RELAY THROUGH THE
TAILLIGHT RELAY COIL, AND TO TERMINAL (A)5 (USA), (B)12 (CANADA) THROUGH THE HEADLIGHT RELAY COIL.
1. NORMAL LIGHTING OPERATION
TURN TAILLIGHT ON
WITH LIGHT CONTROL SW TURNED TO TAILLIGHT POSITION, A SIGNAL IS INPUT INTO TERMINAL (A)3 (USA), (B)10 (CANADA) OF
THE INTEGRATION RELAY. DUE TO THIS SIGNAL, THE CURRENT FLOWING TO TERMINAL (A)4 (USA), (B)11 (CANADA) OF THE RELAY
FLOWS TO TERMINAL (A)3 (USA), (B)10 (CANADA) " TERMINAL 3 OF THE LIGHT CONTROL SW "TERMINAL 4 " TO GROUND AND
TAILLIGHT RELAY CAUSES TAILLIGHT TO TURN ON.
TURN HEADLIGHT ON
WITH LIGHT CONTROL SW TURNED TO HEADLIGHT POSITION, A SIGNAL IS INPUT INTO TERMINALS (A)3 (USA). (B)10 (CANADA)
AND (A)6 (USA), (B)13 (CANADA) OF THE INTEGRATION RELAY. DUE TO THIS SIGNAL, THE CURRENT FLOWING TO TERMINAL (A)5
(USA), (B)12 (CANADA) OF THE RELAY FLOWS TO TERMINAL (A)6 (USA), (B)13 (CANADA) " TERMINAL 13 OF THE LIGHT CONTROL
SW " TERMINAL 4 " TO GROUND IN THE HEADLIGHT CIRCUIT, AND CAUSES TAILLIGHT AND HEADLIGHT RELAY TO TURN ON. THE
TAILLIGHT CIRCUIT IS SAME AS ABOVE.
2. LIGHT AUTO TURN OFF OPERATION
WITH LIGHTS ON AND IGNITION SW TURNED OFF (INPUT SIGNAL GOES TO TERMINAL 7 OF THE RELAY), WHEN DOOR ON DRIVER'S
SIDE IS OPENED (INPUT SIGNAL GOES TO TERMINAL 6 OF THE RELAY), THE RELAY OPERATES AND THE CURRENT IS CUT OFF
WHICH FLOWS FROM TERMINAL (A)4 (USA), (B)11 (CANADA) OF THE RELAY TO TERMINAL (A)3 (USA), (B)10 (CANADA) IN TAILLIGHT
CIRCUIT AND FROM TERMINAL (A)5 (USA), (B)12 (CANADA) TO TERMINAL (A)6 (USA), (B)13 (CANADA) IN HEADLIGHT CIRCUIT.
AS A RESULT, ALL LIGHTS ARE TURNED OFF AUTOMATICALLY.
HEADLIGHT RELAY 1±2 : CLOSED WITH LIGHT CONTROL SW AT HEAD POSITION OR DIMMER SW AT FLASH POSITION
TAILLIGHT RELAY 5±3 : CLOSED WITH LIGHT CONTROL SW AT TA I L OR HEAD POSITION
I16(A)(B) INTEGRATION RELAY
7±GROUND : APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION
6±GROUND : CONTINUITY WITH DOOR LH OPEN
(A) 4, (B) 11±GROUND: ALWAYS APPROX. 12 VOLTS
(A) 5, (B) 12±GROUND: ALWAYS APPROX. 12 VOLTS
(A) 6, (B) 13±GROUND: CONTINUITY WITH LIGHT CONTROL SW AT HEAD POSITION
(A) 3, (B) 10±GROUND: CONTINUITY WITH LIGHT CONTROL SW AT TA I L OR HEAD POSITION
D10 DOOR LOCK MOTOR, DOOR UNLOCK DETECTION SW AND DOOR OPEN DETECTION SW LH
3±6 : CLOSED WITH DOOR LH OPEN
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
C1528F 926I16B29 (CANADA)
D1030I16A29 (USA)
: RELAY BLOCKS
CODESEE PAGERELAY BLOCKS (RELAY BLOCK LOCATION)
219ENGINE COMPARTMENT LEFT
423LEFT KICK PANEL (J/B NO.1 LEFT)
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODESEE PAGEJUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)
1B20ENGINE ROOM MAIN WIRE
1D20FRONT DOOR LH WIRE
1J20COWL WIRE1K20COWL WIRE
: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS
CODESEE PAGEJOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)
IE136ENGINE WIRE AND COWL WIRE (R/B NO.4)
SYSTEM OUTLINE
SERVICE HINTS
WhereEverybodyKnowsYourName

1
2
X
X X
910
D4 I15
BLACK
107
LIQUID CRYSTAL INNER REAR VIEW MIRROR
2
1F
8 1B
5 B212
RY
R
R
R
W± B
10A
DOME
FROM POWER SOURCE
SYSTEM(
SEE PAGE 56 )
INNER MIRROR UNLOCK
WARNING SW
[IGNITION SW]
D4 I15
TO FRONT PERSONAL
LIGHT
DAY/NIGHT
SHIFT SW 1F
9
1I
15
9
10
1H
13
1J
1
1F
YW±B
1 2
D 4 DAY/NIGHT SHIFT SW
1 ± GROUND: ALWAYS APPROX.
12 VOLTS
I15 UNLOCK WARNING SW [IGNITION SW]
10±9: CLOSED WITH IGNITION KEY IN CYLINDER
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
D 430I1529
: RELAY BLOCKS
CODESEE PAGERELAY BLOCKS (RELAY BLOCK LOCATION)
219ENGINE COMPARTMENT LEFT
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODESEE PAGEJUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)
1B20ENGINE ROOM MAIN WIRE
1F20ROOF WIRE
1H
1I20COWL WIRE
1J
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATION
IF36LEFT KICK PANEL
: SPLICE POINTS
CODESEE PAGEWIRE HARNESS WITH SPLICE POINTSCODESEE PAGEWIRE HARNESS WITH SPLICE POINTS
B 240ROOF WIRE
SERVICE HINTS
WhereEverybodyKnowsYourName

198
MOON ROOF
CURRENT IS APPLIED AT ALL TIMES THROUGH POWER FUSE TO TERMINAL 5 OF POWER MAIN RELAY AND ALSO THROUGH DOME
FUSE TO TERMINAL 12 OF MOON ROOF CONTROL RELAY. WITH THE IGNITION SW TURNED ON, THE CURRENT FLOWS TERMINAL 1
OF POWER MAIN RELAY " TERMINAL 2 " TO GROUND THROUGH ECU±IG FUSE. AS A RESULT, POWER MAIN RELAY IS ACTIVATED
AND THE CURRENT TO TERMINAL 5 OF POWER MAIN RELAY FLOWS FROM TERMINAL 3 OF RELAY TO TERMINAL 6 OF MOON ROOF
CONTROL RELAY.
1. SLIDE OPEN OPERATION
WHEN THE IGNITION SW IS TURNED ON AND THE MOON ROOF CONTROL SW IS PUSHED TO THE OPEN POSITION, A SIGNAL IS
INPUT FROM TERMINAL 5 OF MOON ROOF CONTROL SW TO TERMINAL 1 OF MOON ROOF CONTROL RELAY. MOON ROOF LIMIT SW
NO. 2 IS ON AT THIS TIME.
WHEN THIS OCCURS, THE RELAY IS ACTIVATED AND THE CURRENT TO TERMINAL 6 OF MOON ROOF CONTROL RELAY FLOWS
FROM TERMINAL 5 " TERMINAL 3 OF MOON ROOF MOTOR " TERMINAL 1 " TERMINAL 4 OF MOON ROOF CONTROL RELAY "
TERMINAL 11 " TO GROUND AND ROTATES THE MOTOR TO OPEN THE MOON ROOF WHILE THE SW IS BEING PUSHED TO OPEN
POSITION.
2. SLIDE CLOSE OPERATION
WITH THE IGNITION SW TURNED ON, THE MOON ROOF COMPLETELY OPEN AND MOON ROOF LIMIT SW NO. 1 AND NO. 2 BOTH ON,
WHEN THE MOON ROOF CONTROL SW IS PUSHED TO THE CLOSE POSITION A SIGNAL IS INPUT FROM TERMINAL 2 OF MOON
ROOF CONTROL SW TO TERMINAL 2 OF MOON ROOF CONTROL RELAY.
WHEN THIS OCCURS, THE RELAY IS ACTIVATED AND THE CURRENT TO TERMINAL 6 OF MOON ROOF CONTROL RELAY FLOWS
FROM TERMINAL 4 " TERMINAL 1 OF MOON ROOF MOTOR " TERMINAL 3 " TERMINAL 5 OF MOON ROOF CONTROL RELAY "
TERMINAL 11 " TO GROUND AND ROTATES THE MOTOR TO CLOSE THE MOON ROOF WHITE THE SW IS BEING PUSHED TO CLOSE
POSITION.
MOON ROOF LIMIT SW NO. 1 TURNS OFF (LIMIT SW NO. 2 IS ON) AND AT 200MM (7.9 IN) BEFORE FULLY CLOSED POSITION, SIGNAL
IS INPUT FROM TERMINAL 2 OF LIMIT SW NO. 1 TO TERMINAL 8 OF MOON ROOF CONTROL RELAY. THIS SIGNAL ACTIVATES THE
RELAY AND STOPS CONTINUITY FROM TERMINAL 6 OF MOON ROOF CONTROL RELAY TO TERMINAL 11. AS A RESULT, THE MOON
ROOF STOPS AT THIS POSITION.
TO CLOSE THE MOON ROOF COMPLETELY, PUSHING THE MOON ROOF CONTROL SW AGAIN TO THE CLOSE SIDE CAUSES A
SIGNAL TO BE INPUT AGAIN TO TERMINAL 2 OF MOON ROOF CONTROL RELAY. THIS ACTIVATES THE RELAY AND THE MOON ROOF
WILL CLOSE AS LONG AS THE MOON ROOF CONTROL SW IS BEING PUSHED, ALLOWING\
THE MOON ROOF TO FULLY CLOSE.
3. TILT UP OPERATION
WHEN THE MOON ROOF CONTROL SW IS PUSHED TO TILT UP POSITION, WITH THE IGNITION SW TURNED ON AND THE MOON
ROOF COMPLETELY CLOSED (MOON ROOF LIGHT SW NO.2 IS OFF), A SIGNAL IS INPUT FROM TERMINAL 1 OF MOON ROOF
CONTROL SW TO TERMINAL 3 OF MOON ROOF CONTROL RELAY. AS A RESULT, THE RELAY IS ACTIVATED AND THE CURRENT TO
TERMINAL 6 OF RELAY FLOWS FROM TERMINAL 4 OF THE RELAY " TERMINAL 1 OF MOON ROOF MOTOR " TERMINAL 3 "
TERMINAL 5 OF RELAY " TERMINAL 11 TO GROUND AND ROTATES THE MOTOR SO THAT TILT UP OPERATION OCCURS AS LONG
AS THE MOON ROOF CONTROL SW IS PUSHED ON THE TILT UP SIDE.
4. TILT DOWN OPERATION
WHEN THE MOON ROOF CONTROL SW IS PUSHED TO TILT DOWN POSITION, WITH THE IGNITION SW TURNED ON AND THE MOON
ROOF TILTED UP (NO. 1 AND NO. 2 MOON ROOF LIMIT SWITCHES ARE BOTH OFF), A SIGN\
AL IS INPUT FROM TERMINAL 3 OF MOON
ROOF CONTROL SW TO TERMINAL 7 OF MOON ROOF CONTROL RELAY.
AS A RESULT, THE RELAY IS ACTIVATED AND THE CURRENT TO TERMINAL 6 OF RELAY FLOWS FROM TERMINAL 5 OF RELAY "
TERMINAL 3 OF MOON ROOF MOTOR " TERMINAL 1 " TERMINAL 4 OF RELAY " TERMINAL 11 " TO GROUND AND ROTATES THE
MOTOR SO THAT TILT DOWN OPERATION OCCURS AS LONG AS THE MOON ROOF CONTROL SW IS PUSHED ON THE TILT DOWN
SIDE. (DURING TILT DOWN, LIMIT SW NO. 1 IS CHANGED FROM OFF TO ON.)
5. KEY OFF MOON ROOF OPERATION
WITH THE IGNITION SW TURNED FROM ON TO OFF, THE THEFT DETERRENT ECU OPERATES AND CURRENT FLOWS FROM DOOR
FUSE TO TERMINAL (A)8 OF THE ECU OR DOME FUSE TO TERMINAL (A)20 OF THE ECU " TERMINAL (B)8 " TERMINAL 1 OF
POWER MAIN RELAY " TERMINAL 2 " TO GROUND FOR ABOUT 60 SECONDS. THE SAME AS NORMAL OPERATION, THE CURRENT
FLOWS FROM POWER FUSE " TERMINAL 5 OF THE POWER MAIN RELAY " TERMINAL 3 " TERMINAL 6 OF THE MOON ROOF
CONTROL RELAY. AS A RESULT, FOR ABOUT 60 SECONDS AFTER THE IGNITION SW IS TURNED OFF, THE FUNCTIONING OF THIS
RELAY MAKES IT POSSIBLE TO OPEN AND CLOSE THE MOON ROOF. ALSO, BY OPENING THE FRONT DOOR (DOOR DETECT SW
ON) WITHIN ABOUT 60 SECONDS AFTER TURNING THE IGNITION SW TO OFF, A SIGNAL IS INPUT TO TERMINALS (A)12 OR (A)13 OF
THEFT DETERRENT ECU. AS A RESULT, THE ECU TURNS OFF AND OPEN AND CLOSE MOVEMENT OF THE MOON ROOF STOPS.
SYSTEM OUTLINE
WhereEverybodyKnowsYourName

199
6. TILT UP REMINDER SYSTEM
WITH THE IGNITION SW IS TURNED TO ACC OR OFF WITH THE MOON ROOF STILL TILTED UP, KEY OFF MOON ROOF OPERATION
CAUSES CURRENT TO FLOW TO TERMINAL 6 OF THE MOON ROOF CONTROL RELAY FOR A PERIOD OF APPROX. 60 SECONDS OR
UNTIL THE DRIVER'S DOOR OR PASSENGER'S DOOR IS OPENED. WHEN KEY OFF MOON ROOF OPERATION ENDS AND THE
CURRENT FLOW IS STOPPED, THE MOON ROOF CONTROL RELAY RECEIVES A SIGNAL THAT THE IGNITION SW IS OFF. MOON
ROOF LIMIT SW NO. 1 AND NO. 2 ARE OFF AT THIS TIME, SO THE SIGNAL IS INPUT TO TERMINALS 8 AND 9 OF THE MOON ROOF
CONTROL RELAY, INDICATING THAT THE MOON ROOF IS IN THE TILT UP CONDITION. THIS CURRENT TO THE MOON ROOF
CONTROL RELAY FLOWS TO TERMINAL 12 OF RELAY " BUZZER " TERMINAL 11 " GROUND, CAUSING THE BUZZER TO SOUND
FOR APPROX. 8 SECONDS. TO INFORM THE DRIVER THAT THE MOON ROOF IS IN THE TILT UP POSITION.
POWER MAIN RELAY
3±5 : CLOSED WITH IGNITION SW AT ON POSITION
M 2 MOON ROOF CONTROL RELAY
11±GROUND : ALWAYS CONTINUITY 6±GROUND : APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION
4±GROUND : APPROX. 12 VOLTS WITH IGNITION SW ON, AND MOON ROOF CONTROL SW AT CLOSE OR UP POSITION
(EXCEPT APPROX. 200MM (7.9 IN) BEFORE FULLY CLOSED POSITION)
5±GROUND : APPROX. 12 VOLTS WITH IGNITION SW ON, AND MOON ROOF CONTROL SW AT OPEN OR DOWN POSITION
M 3 MOON ROOF CONTROL SW
1±4 : CLOSED WITH MOON ROOF CONTROL SW AT UP POSITION
2±4 : CLOSED WITH MOON ROOF CONTROL SW AT CLOSE POSITION
3±4 : CLOSED WITH MOON ROOF CONTROL SW AT DOWN POSITION
5±4 : CLOSED WITH MOON ROOF CONTROL SW AT OPEN POSITION
4±GROUND : ALWAYS CONTINUITY
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
D1030M 331T 8B29
D1130M4A31T 9A29
M 231M 4B31
: RELAY BLOCKS
CODESEE PAGERELAY BLOCKS (RELAY BLOCK LOCATION)
219ENGINE COMPARTMENT LEFT
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODESEE PAGEJUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)
1B20ENGINE ROOM MAIN WIRE
1D20FRONT DOOR LH WIRE
1F20ROOF WIRE
1H
1I20COWL WIRE1J20COWL WIRE
1K
: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS
CODESEE PAGEJOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)
IP138FRONT DOOR RH WIRE AND COWL WIRE (RIGHT KICK PANEL)
BZ140ROOF WIRE AND MOON ROOF WIRE (FRONT SIDE OF ROOF LEFT)
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATION
IF36LEFT KICK PANEL
IJ36RIGHT KICK PANEL
: SPLICE POINTS
CODESEE PAGEWIRE HARNESS WITH SPLICE POINTSCODESEE PAGEWIRE HARNESS WITH SPLICE POINTS
B 140ROOF WIREB 340MOON ROOF WIRE
SERVICE HINTS
WhereEverybodyKnowsYourName

OVERALL ELECTRICAL WIRING DIAGRAM
1234
1 LEXUS SC300 (
Cont . ne xt pa ge )
2 1
5
3
1J
7 1J
31J 5
3D
1
1B
4 1E
81H 52 2
3D
2
16 IE1
1EB2 15 IE1 3EB1
2
5IJ2 13IJ2 2EB2
1A B B
B
B
L
IG
S 1J
6
1K
4
1
C
1
D
4
ACC
IG1
ST1
IG2
AM1 2
1
6
11 AM2
15 14 2
2
2
1IG3
W
W± R B±Y
B±W
B± O
Y± G
B±YW
B
W± L
W
W± R
W± R
B
W
B±Y W
B
B B
B± W L±O
B B±O
B
B±W
Y± G
Y±G
Y±G
B± Y
W
B
B L±O
Y±G
B
W± R
4 7 9 14 13 5
6
120A ALT
100A AM1 30A I NJ
30A AM2
60A MAIN
F9
FUSE BL OCK
40A I GSW
I15
IGNITION SW
C12
CHARGE WARNING
LIGHT 7. 5A
ENGINE
7. 5A
AL T
SENCI NG
To Integr ation
Relay< 5±4> STARTER
RELAY
7. 5A
ST
N1
NEUTRAL
START SW
To Theft Deterrent
and Door Lock ECU
< 18±3>
To Engine and
ECT ECU< 2±2>
STARTER
AL TERNATOR
BATTERY
2
3
1
Charging Starting
B± O
Y± G
3
4
S6 D , S7 C
(Canada )
12
11
6IJ1
A1 0 B , A11 A 1
23 1
BA
A1 0 A11 BL ACKALTERNATOR 1
1
D
C
START ER
S6
S7 BROWN
Power Source
Y± G
2 1
IJ2 8B B
B± WB±W
(A/ T )
(
A/T )
(M/T )
(
M/T )
B C2 3
CL UTCH
START SW
B
2
3
P
N
B±O
B±O
WhereEverybodyKnowsYourName

567 8
1LEXUSSC300(
Cont ' d )
2EC2 1EC2
7IJ1
1
345
12
B±O
B B
B±O
21
B±O
B±O
BL
B±O
W± L
B±O
W±Y
Y± G
W±Y
Y±G To Engine and ECT ECU º IGT1º < 2±8>
To Engine and ECT ECU º IGF1º < 2±8>
To Check Connec tor º IG±º < 2±4>
IGF IGT +B C±
TAC
I2
IGNITER
NO. 1
I4
IGNITION COIL
NO. 1DI STRI B UT OR
N3
NOISE FILTER
(
for Ignition System )
Ignition
B±O
8IK1 ToComb. MeterºTACHOº<21±7>
B± OB
WhereEverybodyKnowsYourName

OVERALL ELECTRICAL WIRING DIAGRAM
1234
1J
7 1J
31J 6 22
1B
4 1I
51K 42 22
22
2
4
ACC
IG1
ST1 IG2
AM1 2
1
6
11 AM2
32
41 3 1
4
2
21
21
21
21
16 IE1
15 IE1 1 EB22
1BT1 2BT1 3BT1
N P
2
3
21
413
6 14
7
9 17 BT1
21 21 BK EB1J
5
1E
12 7
8
4
15
12
13 1
814 25
1
7IJ2 9IK2 IK1
3A
4
3D
13
3B 1A IK1
IK1
2 1 M 3
W
W±R
W± R W
B± Y
B±R B±R B± Y B±Y
B± R
B± R
L±Y
G±W
B±W
B±O
B±O
L±RW
B±R B±Y B
Y
B±O
B±O
B±O
B±O
B±O
B±O
GR ±YB±R B± Y
B± O
G
G
B
L±O
L±O B
R±GP
G
G
W± B GP
R± G
W± B
W± B L±Y
G±W
YY W±B
B±R
B±YB±W
B± W
W± R
B±O B±O
B±O
B± O
B±O
W
W± B
B±R3 4
G±W W± L
LG
B±Y
B±W
G± R G±Y LG
L±Y
B±R
G± Y
G±R
LG
GR±Y
B± O
B±W B± O
B±R
B±RB± Y
R±G L±Y
G±W B
Y
B
B± Y
B±R W
L±R
B± Y LG
GR±Y
R±L
W
TE1 TE2 TT
ENG
OX 2 OX 1VF1
FP +B
5
G
3
B
W
T6TDCL
C3
CHECK CONNE CT OR
E1
CHECK ENGINE WARNI NG
LIGHT[ COMB. METER]
10A
GA UGE
EFI
MAIN
RELAY
30A
EFI
N1
NE UT RA L
ST ART SW
ST ARTER
RE LA Y
F1 6
FUEL PUMP ECU
BATTERY
F15
FUEL PUMP
30A AM2
60A MAIN
120A ALT
100A AM1
30A I NJ
I11
I NJECTOR No. 6 I10
I NJECTOR No. 5 I9
I NJECTOR No. 4 I7
I NJECTOR No. 2 I8
I NJECTOR No. 3 I6
I NJECTOR No. 1
From Starter< 1±3>
To Thef t Deter rent
and Door Loc k ECU
< 17±3> F9
FUSE BL OCK
7. 5A
ST
7. 5A
IGN
40A
IGSW I15
IGNITION SW
Engine Control
2 LEXUS SC300
GR±YB±R
VF2
TE1
W
W± B
B±Y
17 18
1 2345 6789 10
23
22
21
20
19
15
14
13
12
11 16 12 34 56 78
9 10 1112 13 14 1516 1718
AB
CHECK E NGI NE WA RNI NG
LIGHT[COMB. METER] W
C14 C13 6IJ1
1EB2
IJ112
B±R
B± R
E1
3 BR
25
From Stop Light SW
<5±6><4±6>
C1 3
IG±
From Igniter
ºTACº<1±5>
B,C14 A
19
P
BR
1IJ1 IK1
4
3B
4
Power
Source
(
Cont . ne xt pa ge )
Fr om A/C Contr ol
Assembly
< 22±7> < 22±5>
TC A/ C
P±B P±L4
11
11TC
Fr om A/C Contr ol
Assembly< 22±8> P± B G± Y
IG3
3
B±R
Under the center
pillar LH Fro nt s i de o f
left f ender
7
4
2 1IJ28
B B±W
B
C23
CLUTCH
START SW (
A/T )(
M/ T )
7IJ1
3IJ1B±O B±O
(A/ T )
3 EB1B (
M/T )
*1: (
w/ Traction Control )
* 2:
(
w/oTractionControl )
* 3: (
USA Spec. )
* 4:
(
Ex. USA Sp ec. )
WhereEverybodyKnowsYourName

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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OVERALL ELECTRICAL WIRING DIAGRAM
1234
4 LEXUS SC300
1J
7 221J
81B2
4
1B
5
1B
4 1K
11
22
22
44
1I 1E
3
4
1 2 23
1
5
4
ACC
IG1
ST1
AM1 3
2
1 21
2 1
21
2
19 IE1 12 IE1 5IE1 6IE1
9IG1
4
7
6 4
19 15
1
3 20 16
2
18 4
97 313
6 7
IJ 1J
5
3A 1E 1C
1A
1I
15
1C
1F
1K 3D
7B 1A
2 1 9
10
BK IF 1H
1K 1J 1E W± BY Y
G± O G
G
W± L
Y
Y
W± B
R± Y
W± G
G± W
W± LW± L
W± L W
W± B R± W
W± B
R
L±W P± B
G±L
R± W
R± W
BR± W
B±L
B±L
W±B
W± B
W±B W±B W±B
W±B W±B
R± W
R± W
R± WR± W
R± W R±B R±B
W
G± W
G± W W
P±L
W± L
G G
P±L
B±Y
W
R± Y R±L R
YVPower
Source
F9
FUSE BL OCK60A MAIN 100A AM1
120A ALT
W
R±Y
40A
IGSW
LO
HI
HI
LO
HEADLIGHT LH
HEADLIGHT RH
HEADLIGHT
RELAY
Fr om Connerring Light
Relay< 7±2> DI ODE10A DOME
7. 5A RADIO No. 2
LIGHT
CONTROL
DIMMER
OFF
TAIL
HEAD
LOW
HIGH
FLASH HU HF FL E D T H E L
C15
COMBINATI ON SW
BATTERY
C13
HIGH BEAM
I NDI CA TOR L I GHT
[COMB. METER]
To Door Lock Mot or and
Unlock Detection SW and
Doo r Open De t ect i on S W LH
<17±5><17±6>
To Door Lock Mot or and
Unlock Detection SW and
Doo r Open De t ect i on S W RH
< 17±6>
From Open Door War ning Light
From Per sonal Light< 6±2>
B4
BACKLE SW LH
I15
UNLOCK WARNI NG SW
[IGNITION SW] SEAT BELT WARNI NG
LI GHT[ COMB. MET ER]
5118
TAIL LIGHT
RELAY
To Thef t
Deter rent and
Do or L oc k ECU
< 17±3>
7. 5A PANEL15A TAIL
10A
GAUGE
3 12 2
13 4Y
BELT
H± LP B A CC TRLY I NTB I G
BKL KEY
12 12
9
To Theft Deterr ent and
Door Lock ECU< 17±3>
I15
IGNITION SW
I16
I NTEGRAT I ON REL AY
H
T
G± L
R±G
1 3
2
B±Y
G±O
1C
16DI ODE
1E
1
9
C1 2 , C1 4 AB
6
From Tens ion Reducer
Solenoid LH< 11±7>
Fr om Thef t Deter rent and
Door Loc k ECU< 17±2>
Fr om Day /Night Shift SW< 12±1>
Fr om Tilt and Power Teles copic
ECU< 11±1> Y
Y
B±L
W±B
5C 4C
CC 3 111 12 7
6428 510 GND
INTEGRATI ON RELAY
SEAT BELT
WARNING LIGHT
[COMB. METER]12
3456
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 C
A
B I16
C12
C1 4
Headlight and Light Auto Turn Off (
for USA ) Unlock and Seat Belt Warning
(
for USA )
(
Cont . ne xt pa ge )
2
1
1I 3
R± YR± Y
C6 C
21
Y
Right kic k panel
Under t he c ent er pillar LH Left k ick panel
IG1
8
15A
HEAD
RH
15A
HE AD
LH
W±B R
R
R
R
R
R 6Ba2
Ba1
11
5Ba2 Ba1
12 (
w/ ME MORY )
( w/ o MEMORY )
(
w/ Me mo r y )
( w/ o Memory )
WhereEverybodyKnowsYourName

OVERALL ELECTRICAL WIRING DIAGRAM
1234
5 LEXUS SC300
1J
7 22 2 21J
81B2
4
1B
5
1B
4 1K
11
22 22
22
44
1I 1E
3 1
4 2 3
4
1 2 23
1
5
4
ACC
IG1
ST1
AM1 3
2
1 21 2 1
21
2
19 IE1 12 IE1 11 IE1 5IE1 6IE1
9IG1
4
7
6 4
15 19 21 1
3 16 20 22 2
18 497 313
6 7
IJ 8IG1 1J
5
3A 1E 1C
1A
1I
15
1C
1F
1K 3D
7B 1A
2 1 9
10
BK IF 1H
1K 1J 1E W± BY Y
G± O G
G
W± L
Y
Y
W±B
R
W±B W±B R±YW± G
G± W
W± LW± L
W± L W
W± B
R±W W± B
W± B
R
R
LG±B G±W
L±W P± B
G±L
R± W
R± W
BR± W
B±L
B± L
W± B
W± B
W±B W±B W±B W±B W±B
W± B W± B
R±W
R±W
R
W±B R±B R± W
R± W R±G
R
W
G± W
G± W R
R R
W
P±L W
G G
P±L
B±Y
W
R± Y R±L R
Y VPower
Source
F9
FUSE BL OCK60A MAIN
100A AM1
120A ALT
22W
R±Y
TH
15A
HEAD
LH±LWR
15A HEAD RH±LWR
15A HEAD RH±UPR 15 A HEA D L H± UP R
40A
IGSW
H3LH
H4 RH
H2 RH H1LH
HEADLIGHT
(
LO )
HEADLIGHT (
HI )
DIMMER
RE LA Y HEADLIGHT
RELAY
Fr om Connerring Light
Relay< 8±7> DI ODE10A DOME
7. 5A RADIO No. 2
LIGHT
CONTROL
DIMMER
OFF
TAI L
HE AD
LOW
HI GH
FLASH ED HL HU HF EL T H
C15
COMBINATI ON
SW
BATTERY
C13
HIGH BEAM
I NDI CA TOR L I GHT
[COMB. METER]
To Door Lock Mot or and
Unlock Detection SW and
Doo r Open De t ect i on S W LH
< 17±1>
To Door Lock Mot or and
Unlock Detection SW and
Doo r Open De t ect i on S W RH
< 17±1> From Open Door War ning Light
From Per sonal Light< 6±2>
B4
BACKLE SW LH
I15
UNLOCK WARNING SW
[IGNITION SW] SEAT BELT WARNI NG
LI GHT[ COMB. MET ER]
5118
TAIL LIGHT
RELAY
To Thef t
Deter rent and
Do or L oc k ECU
< 17±3>
7. 5A PANEL15A TAIL
10A
GAUGE
3 12 2
13 4Y
BELT
H± LP B A CC TA I L I NTB I G
BKL KEY
12 2
9
To Thef t Deter rent
and Door Loc k ECU
< 17±3>
I15
IGNITION SW
I16
I NTEGRAT I ON REL AY
DIM TOUT
HF
HU
Y± B
R±L
CHG± P KBY±G
B
From Alternator º Lº < 1±2>
From Park ing Br ake SW < 21±2>
1 3 2
B±Y
G± O
1C
16DI ODE
1E
1
9
C1 2 , C1 4 AB
6
From Tens ion Reducer
Solenoid LH< 11±7>
Fr om Thef t Deter rent and
Door Loc k ECU< 17±2>
Fr om Day /Night Shift SW< 12±1>
Fr om Tilt and Power Teles copic
ECU< 11±1> Y
Y
W±B
12C 11C 5C
CCC CC 4C2C 9 8 7 10 13 111 12 7
642 8 105 GND
I NTEGRATI ON REL AY
SEAT BELT
WARNING LIGHT
[COMB. METER]
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 C
A
B I16
C12
C1 4
Headlight (
for Canada ) Unlock and
Seat Belt Warning
(
for Canada )
(
Cont . ne xt pa ge )
2
1
3C 1C
13
Y
12345678910111213
18
17
IG
W±B
6Ba2Ba 1
11
5Ba2 Ba 1
12 (
w/ Memor y )
( w/o Memory )
B±L
( w/ Memor y )
( w/o Memory )
XX
Right kic k panel
Unlock the center
pillar LHLeft kic k
panel
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