key LEXUS SC400 1991 Service Manual Online
[x] Cancel search | Manufacturer: LEXUS, Model Year: 1991, Model line: SC400, Model: LEXUS SC400 1991Pages: 4087, PDF Size: 75.75 MB
Page 4003 of 4087

58
POWER SOURCE
HEADLIGHT RELAY (FOR USA)1±2 : CLOSED WITH LIGHT CONTROL SW AT HEAD POSITION OR DIMMER SW AT FLASH POSITION
HEADLIGHT RELAY (FOR CANADA) 1±2 : CLOSED WITH LIGHT CONTROL SW AT HEAD POSITION OR DIMMER SW AT FLASH POSITION
: CLOSED WITH ENGINE RUNNING AND PARKING BRAKE PEDAL RELEASED (PARKING BRAKE SW OFF)
TAILLIGHT RELAY (FOR USA) 5±3 : CLOSED WITH LIGHT CONTROL SW AT TAIL OR HEAD POSITION
TAILLIGHT RELAY (FOR CANADA) 5±3 : CLOSED WITH LIGHT CONTROL SW AT TAIL OR HEAD POSITION
: CLOSED WITH ENGINE RUNNING AND PARKING BRAKE PEDAL RELEASED (PARKING BRAKE SW OFF)
IGNITION MAIN RELAY 2±1 : CLOSED WITH IGNITION KEY AT ON OR ST POSITION
I15 IGNITION SW
4±3 : CLOSED WITH IGNITION KEY AT ACC OR ON POSITION
4±2 : CLOSED WITH IGNITION KEY AT ON OR ST POSITION
11±6: CLOSED WITH IGNITION KEY AT ON OR ST POSITION
4±1 : CLOSED WITH IGNITION KEY AT ST POSITION
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
C2328I1529
F 926N 127
: 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
1J20COWL WIRE1K20COWL WIRE
: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS
CODESEE PAGEJOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)
EB134ENGINE WIRE AND ENGINE ROOM MAIN WIRE (FRONT SIDE OF R/B NO. 2)
IE136ENGINE ROOM MAIN WIRE AND COWL WIRE (R/B NO. 4)
IJ136ENGINE WIRE AND COWL WIRE (RIGHT KICK PANEL)IJ236ENGINE WIRE AND COWL WIRE (RIGHT KICK PANEL)
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATION
IF36LEFT KICK PANEL
: SPLICE POINTS
CODESEE PAGEWIRE HARNESS WITH SPLICE POINTSCODESEE PAGEWIRE HARNESS WITH SPLICE POINTS
I 138COWL WIREI2438ENGINE ROOM MAIN WIRE
I1138COWL WIREI3338ENGINE WIRE
SERVICE HINTS
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Page 4004 of 4087

122
POWER WINDOW
2
1H
10
1D
8 1J
11D 10 1D 91J 2
1B
5
1I
16
6 3 6
3
IF IJ IP1
20 IP1
15
B4 8
31
1I
7
24
A
20 A 8A2
A
16 A 13 A12 4
B 8
R
R
L±WB±R
W±B
W±B L
LW±B
R±B
R±W
W±B
W±B
W±B
W±B R±W
R±W
W±B
W±B
W±B
L
R±W
R±W
L
W±B W±B Y±R
10A
DOME
30A
DOOR15A
ECU±IG 30A
POWER
KEY OFF POWER
CIRCUIT POWER
MAIN
RELAY
DOOR OPEN
DE TE CTION SW RHDOOR OPEN
DE TECTION S W LH
THEFT DETERRENT
AND DOOR LOCK ECU
POWERWINDOWMASTERAND
DOOR LOCK CONTROL SW LH
DOOR LOCK
T8 ,T9
B A
1 2
1K
71K 13
FROM POWER SOURCE SYSTEM
(
SEE PAGE 56 )
D10
D11
P5
62
51
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Page 4006 of 4087

124
POWER WINDOW
WITH THE IGNITION SW TURNED ON, CURRENT FLOWS THROUGH THE ECU±IG FUSE " TERMINAL (A)2 OF THE THEFT
DETERRENT ECU " (B)8 " TERMINAL 2 OF THE POWER MAIN RELAY " TERMINAL 3 " TO GROUND, THIS ACTIVATES THE RELAY
AND THE CURRENT FLOWING TO TERMINAL 4 OF THE RELAY FROM POWER FUSE FLOWS TO TERMINAL 1 OF THE RELAY "
TERMINAL 4 OF THE POWER WINDOW MASTER SW, TERMINAL 3 OF THE POWER WINDOW SW.
1. MANUAL OPERATION (DRIVER'S WINDOW)
WITH THE IGNITION SW TURNED ON AND WITH THE POWER WINDOW MASTER SW (DRIVER'S) IN UP POSITION, THE CURRENT
FLOWING TO TERMINAL 4 OF THE POWER WINDOW MASTER SW FLOWS TO TERMINAL 10 OF THE MASTER SW " TERMINAL 1 OF
THE POWER WINDOW MOTOR " TERMINAL 2 " TERMINAL 9 OF THE MASTER SW " TERMINAL 8 " TO GROUND AND CAUSES
THE POWER WINDOW MOTOR TO ROTATE IN THE UP DIRECTION. THE WINDOW ASCENDS ONLY WHILE THE SW IS BEING PUSHED.
IN DOWN OPERATION, THE FLOW OF CURRENT FROM TERMINAL 4 OF THE POWER WINDOW MASTER SW TO TERMINAL 9 OF THE
MASTER SW CAUSES THE FLOW OF CURRENT FROM TERMINAL 2 OF THE MOTOR " TERMINAL 1 " TERMINAL 10 OF THE
MASTER SW " TERMINAL 8 " TO GROUND, FLOWING IN THE OPPOSITE DIRECTION TO MANUAL UP OPERATION AND CAUSING
THE MOTOR TO ROTATE IN REVERSE, LOWERING THE WINDOW.
2. DRIVER'S WINDOW AUTO DOWN OPERATION
WHEN THE DRIVER'S WINDOW SW IS PUSHED STRONGLY ON THE DOWN SIDE, THE CURRENT FLOWING TO TERMINAL 4 OF THE
POWER WINDOW MASTER SW FLOWS TO THE DOWN CONTACT POINT AND AUTO DOWN CONTACT POINT OF THE DRIVER'S SW.
THIS ACTIVATES THE RELAY (DOWN SIDE) INSIDE THE POWER WINDOW MASTER SW AND THE HOLD CIRCUIT ALSO TURNS ON AT
THE SAME TIME, SO THE RELAY (DOWN SIDE) REMAINS ACTIVATED EVEN WHEN THE SW IS RELEASED.
CURRENT FLOWS AT THIS TIME FROM TERMINAL 4 OF THE POWER WINDOW MASTER SW " TERMINAL 9 " TERMINAL 2 OF
POWER WINDOW MOTOR " MOTOR " TERMINAL 1 " TERMINAL 10 OF POWER WINDOW MASTER SW " TERMINAL 8 " GROUND,
SO THE MOTOR CONTINUES TO OPERATE UNTIL THE DRIVER'S WINDOW IS FULLY DOWN.
WHEN THE DRIVER'S WINDOW FINISHES DOWN OPERATION THE HOLD CIRCUIT GOES OFF, SO THE RELAY (DOWN SIDE) ALSO
TURNS OFF. THIS STOPS THE CURRENT FLOW FROM TERMINAL 4 OF THE POWER WINDOW MASTER SW TO TERMINAL 9, SO THE
POWER WINDOW MOTOR STOPS AND AUTO DOWN OPERATION STOPS.
WHEN THE DRIVER'S SW IS PULLED ON THE UP SIDE DURING AUTO DOWN OPERATION, THE HOLD CIRCUIT IS TURNED OFF SO
CURRENT FLOW FROM TERMINAL 4 OF THE POWER WINDOW MASTER SW TO TERMINAL 9 IS CUT OFF AND THE POWER WINDOW
MOTOR STOPS. IF THE SW REMAINS PULLED UP THE RELAY (UP SIDE) IS ACTIVATED, SO CURRENT FLOWS FROM TERMINAL 4 OF
THE POWER WINDOW MASTER SW " TERMINAL 10 " TERMINAL 1 OF POWER WINDOW MOTOR " MOTOR " TERMINAL 2 "
TERMINAL 9 " TERMINAL 8 " GROUND, THE POWER WINDOW MOTOR ROTATES IN THE UP DIRECTION AND MANUAL UP
OPERATION OCCURS WHILE THE SWITCH IS PULLED UP.
3. MANUAL OPERATION BY POWER WINDOW SW (PASSENGER'S WINDOW)
WITH POWER WINDOW SW (PASSENGER'S) PULLED TO THE UP SIDE, CURRENT FLOWING FROM TERMINAL 3 OF THE POWER
WINDOW CONTROL SW FLOWS TO TERMINAL 5 OF THE POWER WINDOW SW " TERMINAL 1 OF THE POWER WINDOW MOTOR "
TERMINAL 2 " TERMINAL 1 OF THE POWER WINDOW SW " TERMINAL 2 " TERMINAL 7 OF THE MASTER SW " TERMINAL 8 " TO
GROUND AND CAUSES THE POWER WINDOW MOTOR (PASSENGER'S) TO ROTATE IN THE UP DIRECTION. UP OPERATION
CONTINUES ONLY WHILE THE POWER WINDOW SW IS PULLED TO THE UP SIDE. WHEN THE WINDOW DESCENDS, THE CURRENT
FLOWING TO THE MOTOR FLOWS IN THE OPPOSITE DIRECTION, FROM TERMINAL 2 TO TERMINAL 1, AND THE MOTOR ROTATES IN
REVERSE. WHEN THE WINDOW LOCK SW IS PUSHED TO THE LOCK SIDE, THE GROUND CIRCUIT TO THE PASSENGER'S WINDOW
BECOMES OPEN.
AS A RESULT, EVEN IF OPEN/CLOSE OPERATION OF THE PASSENGER'S WINDOW IS TRIED, THE CURRENT FROM TERMINAL 8 OF
THE POWER WINDOW MASTER SW IS NOT GROUNDED AND THE MOTOR DOES NOT ROTATE, SO THE PASSENGER'S WINDOW CAN
NOT BE OPERATED AND WINDOW LOCK OCCURS.
4. KEY OFF POWER WINDOW 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 2 OF
POWER MAIN RELAY " TERMINAL 3 " TO GROUND FOR ABOUT 60 SECONDS. THE SAME AS NORMAL OPERATION, THE CURRENT
FLOWS FROM POWER FUSE " TERMINAL 4 OF THE POWER MAIN RELAY " TERMINAL 1 " TERMINAL 4 OF THE POWER WINDOW
MASTER SW AND TERMINAL 5 OF THE POWER WINDOW SW. AS A RESULT, FOR ABOUT 60 SECONDS AFTER THE IGNITION SW IS
TURNED OFF, THE FUNCTIONING OF THIS RELAY MAKES IT POSSIBLE TO RAISE AND LOWER THE POWER WINDOW. 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 UP AND
DOWN MOVEMENT OF THE POWER WINDOW STOPS.
SYSTEM OUTLINE
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Page 4022 of 4087

166POWER TILT AND POWER TELESCOPIC
THIS SYSTEM OPERATES WITH BOTH THE TILT FUNCTION AND TELESCOPIC FUNCTION DRIVEN AUTOMATICALLY BY THE MOTOR
AND CONTROLLED BY THE ECU. THE STEERING CAN BE ADJUSTED STEPLESSLY FORWARD AND BACK, AND UP AND DOWN, TO
PROVIDE THE MOST SUITABLE STEERING POSITION FOR EASY DRIVING, WITH AUTOMATIC MOVEMENT OF THE STEERING TO A
POSITION WHICH FACILITATES GETTING IN AND OUT OF THE VEHICLE.
THE DRIVER CAN HAVE THE MOST APPROPRIATE DRIVING POSITION MEMORIZED BY OPERATING THE POWER SEAT AND REMOTE
CONTROL MIRROR TOGETHER WITH THE TILT AND POWER TELESCOPIC STEERING.
CURRENT IS ALWAYS APPLIED THROUGH THE
POWER FUSE TO TERMINAL +B OF THE TILT AND POWER TELESCOPIC ECU AND
THROUGH THE DOME FUSE TO TERMINAL BATT OF TILT AND POWER TELESCOPIC ECU.
WITH THE IGNITION SW TURNED ON, THE CURRENT FLOWS FROM ECU±IG FUSE TO TERMINAL IG AND FROM GAUGE FUSE TO
TERMINAL 9 OF A/T INDICATOR SW.
1. MANUAL TILT OPERATION
WHEN THE IGNITION KEY IS INSERTED INTO THE IGNITION KEY CYLINDER (UNLOCK WARNING SW ON), A SIGNAL IS INPUT TO
TERMINAL UWSW OF TILT AND POWER TELESCOPIC ECU. IF THE MANUAL SW IS PUSHED TO THE ªTILT UPº SIDE, CURRENT
FLOWS FROM TERMINAL VC OF TILT AND POWER TELESCOPIC ECU TO TERMINAL MSW OF TILT AND POWER TELESCOPIC ECU
PASSING THROUGH THE MANUAL SW. (THE ECU DETECTS THE MANUAL SW POSITION BY THE VOLUME OF CURRENT.)
AS A RESULT, TILT AND POWER TELESCOPIC ECU OPERATES AND THE CURRENT TO TERMINAL +B OF ECU FLOWS FROM
TERMINAL TIM+ " TERMINAL 1 OF COMB. SW " TERMINAL 2 OF TILT CONTROL MOTOR " TERMINAL 1 " TERMINAL 10 OF COMB.
SW "TERMINAL TIM± OF TILT AND POWER TELESCOPIC ECU " TERMINAL GND2 "GROUND , AND THE TILT UP FUNCTION
OPERATES AS LONG AS THE MANUAL SW IS PUSHED TO THE ªTILT UPº SIDE.
FOR ªTILT DOWNº OPERATION, WHEN THE MANUAL SW IS PUSHED TO THE DOWN SIDE, THE CURRENT FLOWING FROM ECU TO
MOTOR FLOWS TO TERMINAL TIM± OF TILT AND POWER TELESCOPIC ECU "TERMINAL 10 OF COMB. SW "TERMINAL 1 OF TILT
CONTROL MOTOR "TERMINAL 2 "TERMINAL 1 OF COMB. SW "TERMINAL TIM+ OF TILT AND POWER TELESCOPIC ECU, SO THE
MOTOR ROTATES IN THE REVERSE DIRECTION TO TILT UP OPERATION, AND TILT DOWN OPERATION OCCURS ONLY WHILE THE
MANUAL SW IS BEING PUSHED.
2. MANUAL TELESCOPIC OPERATION
WHEN THE IGNITION KEY IS INSERTED INTO THE IGNITION KEY CYLINDER (UNLOCK WARNING SW ON), A SIGNAL IS INPUT TO
TERMINAL UWSW OF TILT AND TELESCOPIC ECU. WHEN THE MANUAL SW IS PUSHED TOWARD ªTELESCOPIC SHORTº SIDE,
CURRENT FLOWS FROM TERMINAL VC OF TILT AND POWER TELESCOPIC ECU TO TERMINAL MSW OF TILT AND POWER
TELESCOPIC ECU THROUGH THE MANUAL SW.
AS A RESULT, THE TILT AND POWER TELESCOPIC ECU OPERATES AND THE CURRENT TO TERMINAL +B OF TILT AND POWER
TELESCOPIC ECU FLOWS FROM TERMINAL TEM+ OF TILT AND POWER TELESCOPIC ECU "TERMINAL 1 OF COMB. SW "
TERMINAL 2 OF TELESCOPIC CONTROL MOTOR "TERMINAL 1 "TERMINAL 4 OF COMB. SW "TERMINAL TEM± OF TILT AND
POWER TELESCOPIC ECU " TERMINAL GND2 "GROUND , AND ªTELESCOPIC SHORTº OPERATION OCCURS AS LONG AS THE
MANUAL SW IS PUSHED THE TO ªTELESCOPIC SHORTº SIDE.
FOR ªTELESCOPIC LONGº OPERATION, WHEN THE MANUAL SW IS PUSHED TO THE TELESCOPIC LONG SIDE, CURRENT FLOWING
FROM TILT AND POWER TELESCOPIC ECU TO THE MOTOR FLOWS THROUGH TERMINAL TEM± OF TILT AND POWER TELESCOPIC
ECU " TERMINAL 4 OF COMB. SW "TERMINAL 1 OF TELESCOPIC CONTROL MOTOR "TERMINAL 2 " TERMINAL 1 OF COMB. SW
" TERMINAL TEM+ OF TILT AND POWER TELESCOPIC ECU "TERMINAL GND2 "GROUND .
AS A RESULT, THE MOTOR ROTATES IN REVERSE TO THE TELESCOPIC SHORT MODE AND TELESCOPIC LONG OPERATION
OCCURS AS LONG AS THE MANUAL SW IS PUSHED TO THE ªTELESCOPIC LONGº SIDE.
3. AUTO AWAY OPERATION
WHEN THE IGNITION SW IS TURNED FROM ON TO OFF, THE CURRENT STOPS FLOWING FROM ECU±IG TO TERMINAL IG OF TILT
AND POWER TELESCOPIC ECU AND IS INPUT AS A SIGNAL THAT THE IGNITION SW IS OFF. WHEN THE AUTO SW IS TURNED ON, AN
ªAUTO SW ONº SIGNAL IS INPUT TO TERMINAL ASW OF TILT AND POWER TELESCOPIC ECU.
IF THE IGNITION KEY IS REMOVED FROM THE IGNITION KEY CYLINDER (UNLOCK WARNING SW OFF) AT THIS TIME, A SIGNAL IS
INPUT FROM TERMINAL UWSW OF TILT AND POWER TELESCOPIC ECU. ALSO, THE TILT POSITION SENSOR (COMB. SW) INPUTS
INTO TERMINAL TIS OF THE TILT AND TELESCOPIC ECU A SIGNAL OF THE STEERING TILT POSITION JUST BEFORE THE IGNITION
SW (FOR UNLOCK WARNING) IS TURNED FROM ON TO OFF.
AS A RESULT, THE TILT AND POWER TELESCOPIC ECU OPERATES AND THE CURRENT TO TERMINAL +B OF TILT AND POWER
TELESCOPIC FLOWS FROM TERMINAL TIM+ OF TILT AND POWER TELESCOPIC ECU "TERMINAL 1 OF COMB. SW "TERMINAL 2
OF TILT CONTROL MOTOR "TERMINAL 1 "TERMINAL 10 OF COMB. SW "TERMINAL TIM± OF TILT AND POWER TELESCOPIC ECU
" TERMINAL GND2 "GROUND , CAUSING THE MOTOR TO ROTATE SO THAT ªTILT UPº OPERATION OCCURS AUTOMATICALLY.
AT THE SAME TIME, THE CURRENT FROM TERMINAL +B OF TILT AND POWER TELESCOPIC ECU TO TERMINAL TEM+ FLOWS FROM
TERMINAL 1 OF COMB. SW "TERMINAL 2 OF TELESCOPIC CONTROL MOTOR "TERMINAL 1 "TERMINAL 4 OF COMB. SW "
TERMINAL TEM± OF TILT AND POWER TELESCOPIC ECU "TERMINAL GND2 "GROUND , CAUSING THE MOTOR TO ROTATE SO
THAT TELESCOPIC SHORT OPERATION OCCURS ON AUTO AND WITH TILT UP OPERATION OCCURRING SIMULTANEOUSLY ON
AUTO, AUTO AWAY OPERATION OCCURS.
SYSTEM OUTLINE
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167
4. AUTO RETURN OPERATION
WHEN THE STEERING IS IN ªAUTO AWAYº CONDITION AND THE IGNITION KEY IS INSERTED INTO THE IGNITION KEY CYLINDER
(UNLOCK WARNING SW ON), A SIGNAL IS INPUT TO TERMINAL UWSW OF TILT AND POWER TELESCOPIC ECU.
AS A RESULT, THE TILT AND POWER TELESCOPIC ECU OPERATES AND THE CURRENT TO TERMINAL +B OF TILT AND POWER
TELESCOPIC ECU FLOWS FROM TERMINAL TEM± OF TILT AND POWER TELESCOPIC ECU "TERMINAL 4 OF COMB. SW "
TERMINAL 1 OF TELESCOPIC CONTROL MOTOR "TERMINAL 2 " TERMINAL 1 OF COMB. SW " TERMINAL TEM+ OF TILT AND
POWER TELESCOPIC ECU " TERMINAL GND2 "GROUND , AND AT THE SAME TIME, CURRENT FLOWS FROM TERMINAL TIM± OF
TILT AND POWER TELESCOPIC ECU "TERMINAL 10 OF COMB. SW "TERMINAL 1 OF TILT CONTROL MOTOR "TERMINAL 2 "
TERMINAL 1 OF COMB. SW "TERMINAL TIM+ OF TILT AND POWER TELESCOPIC ECU "TERMINAL GND2 "GROUND , CAUSING
BOTH THE TILT CONTROL MOTOR AND TELESCOPIC CONTROL MOTOR TO ROTATE. THE MOTORS CONTINUE TO ROTATE UNTIL
THE SIGNALS INPUT FROM THE TILT POSITION SENSOR TO TERMINAL TIS OF TILT AND POWER TELESCOPIC ECU AND FROM THE
TELESCOPIC POSITION SENSOR TERMINAL TES OF TILT AND POWER TELESCOPIC ECU (SIGNALS INFORMING THE ECU OF THE
CURRENT POSITION OF THE STEERING) MATCH THE POSITION MEMORIZED BY THE ECU PRIOR TO AUTO AWAY OPERATION.
IN THIS WAY, THE STEERING POSITION IS AUTOMATICALLY RETURNED TO THE ORIGINAL POSITION.
WHEN THE IGNITION SW IS TURNED FROM OFF TO ON OR THE SHIFT LEVER IS SHIFTED TO A POSITION OTHER THAN P OR N,
AUTO OPERATION IS STOPPED.
C15 TILT AND POWER TELESCOPIC UNIT [COMB. SW]
4±6 : APPROX. 160 WITH TELESCOPIC LONG OPERATION
: APPROX. 360 WITH TILT UP OPERATION
: APPROX. 790 WITH TELESCOPIC SHORT OPERATION
: APPROX. 2.0K WITH TILT DOWN OPERATION
8±7 : CONTINUITY WITH AUTO SW OFF
8±4 : APPROX. 5K
T 7 (D) TELESCOPIC POSITION SENSOR
6±3 : APPROX. 5K
D10 DOOR LOCK MOTOR, DOOR UNLOCK DETECTION SW AND DOOR OPEN DETECTION SW LH
3±6GROUND :CLOSED WITH FRONT DOOR LH OPEN
D12 DRIVING POSITION MEMORY AND RETURN SW
2±3 : CLOSED WITH DRIVING POSITION MEMORY SW (NO. 1) ON
1±3 : CLOSED WITH DRIVING POSITION MEMORY SW (NO. 2) ON
4±3 : CLOSED WITH DRIVING POSITION MEMORY SW (SET) ON
I15 UNLOCK WARNING SW [IGNITION SW]
9±10: CLOSED WITH IGNITION KEY IN CYLINDER
N 1 A/T INDICATOR SW [NEUTRAL START SW]
9±1 : CLOSED WITH SHIFT LEVER AT P POSITION
T10, T11 TILT AND POWER TELESCOPIC ECU
(A) 4±GROUND : ALWAYS APPROX. 12 VOLTS
(A) 1±GROUND : APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION
(B) 18±GROUND : ALWAYS APPROX. 12 VOLTS
(A) 6±GROUND : APPROX. 12 VOLTS WITH IGNITION SW ON AND SHIFT LEVER AT ªPº RANGE
(B) 10±GROUND : CONTINUITY WITH IGNITION KEY IN CYLINDER
(A) 7±GROUND : ALWAYS CONTINUITY
(B) 8±GROUND : ALWAYS CONTINUITY
(B) 2±GROUND : CONTINUITY WITH FRONT DOOR LH OPEN
(B) 3±GROUND : CONTINUITY WITH DRIVING POSITION MEMORY SW (NO. 1) ON
(B) 12±GROUND : CONTINUITY WITH DRIVING POSITION MEMORY SW (NO. 2) ON
(B) 11±GROUND : CONTINUITY WITH DRIVING POSITION MEMORY SW (SET) ON
(A) 10±GROUND : APPROX. 12 VOLTS WITH TILT UP OPERATION
(A) 3±GROUND : APPROX. 12 VOLTS WITH TILT DOWN OPERATION
(A) 2±GROUND : APPROX. 12 VOLTS WITH TELESCOPIC SHORT OPERATION
(A) 11±GROUND : APPROX. 12 VOLTS WITH TELESCOPIC LONG OPERATION
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
C1728N 127T 732
D1030P 329T10B29
D1230P1127T11A29
I1529R 732
SERVICE HINTS
WhereEverybodyKnowsYourName
Page 4051 of 4087
![LEXUS SC400 1991 Service Manual Online
188
SHIFT LOCK
1E
21E 17 1I 10
7 8 SHIFT LOCK
CONTROL SW
SHIFT LOCK
SOLENOID
TIMER
3
2 4
5
1
P1
±P
P2
SLS±
SLS+
1 2
IF 15A
CIG
15A
ECU±IG 15A
STOP
KEY INTERLOCK
SOLENOID
[IGNITION SW] STOP LIGHT
S LEXUS SC400 1991 Service Manual Online
188
SHIFT LOCK
1E
21E 17 1I 10
7 8 SHIFT LOCK
CONTROL SW
SHIFT LOCK
SOLENOID
TIMER
3
2 4
5
1
P1
±P
P2
SLS±
SLS+
1 2
IF 15A
CIG
15A
ECU±IG 15A
STOP
KEY INTERLOCK
SOLENOID
[IGNITION SW] STOP LIGHT
S](/img/36/57051/w960_57051-4050.png)
188
SHIFT LOCK
1E
21E 17 1I 10
7 8 SHIFT LOCK
CONTROL SW
SHIFT LOCK
SOLENOID
TIMER
3
2 4
5
1
P1
±P
P2
SLS±
SLS+
1 2
IF 15A
CIG
15A
ECU±IG 15A
STOP
KEY INTERLOCK
SOLENOID
[IGNITION SW] STOP LIGHT
SW
ACC IG STP
KLS+ EL±RL
G±W G
G±R
V
W±B
W±B W±B
L±R
B±R
G±W G±W W B±R
L±R
SHIFT LOCK ECU
FROM POWER SOURCE SYSTEM
(
SEE PAGE 56 )
I15 S12
S10
1H
1
3A
5
3G
6
1E
20
IG1
12
1H
13
1J
1 1E
18
V
3A
1 3H
15
W±B
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Page 4052 of 4087

189
WHEN THE IGNITION SW IS TURNED TO ACC POSITION THE CURRENT FROM THE CIG FUSE FLOWS TO TERMINAL 1 OF THE SHIFT
LOCK ECU, IN THE ON POSITION, THE CURRENT FROM THE ECU±IG FUSE FLOWS TO TERMINAL 5 OF THE ECU.
1. SHIFT LOCK MECHANISM
WITH THE IGNITION SW ON, WHEN A SIGNAL THAT THE BRAKE PEDAL IS DEPRESSED (STOP LIGHT SW ON) AND A SIGNAL THAT
THE SHIFT LEVER IS PUT IN ªPº RANGE (CONTINUITY BETWEEN P1 AND P OF THE SHIFT LOCK CONTROL SW) IS INPUT TO THE
ECU, THE ECU OPERATES AND CURRENT FLOWS FROM TERMINAL 5 OF THE ECU " TERMINAL SL+ OF THE SHIFT LOCK
SOLENOID " SOLENOID " TERMINAL SL± " TERMINAL 3 OF THE ECU " GROUND. THIS CAUSES THE SHIFT LOCK SOLENOID TO
TURN ON (PLATE STOPPER DISENGAGES) AND THE SHIFT LEVER CAN SHIFT INTO RANGE OTHER THAN THE ªPº RANGE.
2. KEY INTER LOCK MECHANISM
WITH THE IGNITION SW ON OR ACC POSITION, WHEN THE SHIFT LEVER IS PUT IN ªPº RANGE (NO CONTINUIT\
Y BETWEEN P2 AND P
OF SHIFT LOCK CONTROL SW), THE CURRENT FLOWING FROM TERMINAL 2 OF THE ECU " KEY INTER LOCK SOLENOID IS CUT
OFF. THIS CAUSES THE KEY INTER LOCK SOLENOID TO TURN OFF (LOCK LEVER DISENGAGES FROM LOCK POSITION) AND THE
IGNITION KEY CAN BE TURNED FROM ACC TO LOCK POSITION. IF THE IGNITION IS LEFT IN ACC OR ON POSITION WITH THE SHIFT
LEVER IN OTHER THAN ªPº RANGE, THAN AFTER APPROX. ONE HOUR THE ECU\
OPERATES TO RELEASE THE LOCK.
S10 SHIFT LOCK ECU
1±GROUND : APPROX. 12 VOLTS WITH IGNITION SW AT ACC OR ON POSITION
5±GROUND : APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION
3±GROUND : ALWAYS CONTINUITY
4±GROUND : APPROX. 12 VOLTS WITH BRAKE PEDAL DEPRESSED
S12 STOP LIGHT SW
2±1 : CLOSED WITH BRAKE PEDAL DEPRESSED
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
I1529S1029S1229
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODESEE PAGEJUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)
1E20INSTRUMENT PANEL WIRE
1H
1I20COWL WIRE
1J
20COWL WIRE
3A
3G22INSTRUMENT PANEL WIRE
3H
: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS
CODESEE PAGEJOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)
IG136INSTRUMENT PANEL WIRE AND COWL WIRE (R/B NO. 5)
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATION
IF36LEFT KICK PANEL
X 78 12345
12
I15 S 10 S 12
BLACK
SYSTEM OUTLINE
SERVICE HINTS
WhereEverybodyKnowsYourName
Page 4070 of 4087

11 2
THEFT DETERRENT AND DOOR LOCK CONTROL
2
1I
14
1K
13
1K
11 2
3A
1
1J
1
1B
22
1H
13 3F
7
1E
18 1I
16 4
4
1D
8 1H
10 1B
5
1D 10 I8
I11
I11
B4
9
10
1 2IE1
6
IG1
17 IF2 15 IF214
IF2
16 IF2 18 IF2 5IF24
IF2
7
B
13
TAIL B
5
HE AD A
2
IG B
7
ACC A
20
+B1
A
16 E
A
6 KSW
A
19 TSW
A
14 L1
A
10 UL3
A
13 DSWD
A
11 LSWD
A
17 L2
A
18 UL2
1
13
6 4
7 24
2
31
8
21
IF 2 1
M
64 5 31 2
FROM POWER SOURCE SYSTEM
(
SEE PAGE 56 )
60A MAIN
120A ALT
100A AM1
LOCK
UNLOCK
LOCK
UNLOCK
15A
ECU±IG 15A
CIG10A
DOME
HEA DLIGHT
RELAY
G±Y
G±Y
G±L
R±B
L±W
L±R
W±B
W±B
W±B
W±L W
W
B±RL±R R
R
R±Y
G±W
W±B
Y
L
G±Y G G±Y
R±B
W±L
R±BG± L
R±B
G±L
L±W
L±W
R±W
L±W
L±W
R±BG±L
W±B L±R
W±B W±B W±B
G
G±Y L
W±B
W±B W±B
R±YTAI L LI GHT
RELAY
W±LW
TO FUSE º 15A TAILº
THEFT DETERRENT AND DOOR LOCK ECU
UNLOCK WA RNING SW
[IGNITION SW]
LUGGAGE COMPARTMENT
DOOR OPENER SW
DOOR KEY LOCK AND
UNLOCK SW LH
DOOR LOCK MOTOR,
DOOR UNLOCK DETE CTION AND
DOOR OPEN DETECTION SW LH
POWERWINDOWMASTERAND
DOOR LOCK CONTROL SW LH
FUSE BLOCK
L±R
BATTERY
F9
I15
L1
D7
D10
P5
T8 , T9 B A
DIODE
32 51 2
W±B
WhereEverybodyKnowsYourName
Page 4071 of 4087

11 3
M
64 5 31 2
1K
4
2
2
2 2
I11
B7 B7 I11
EB1
3 IE1
15
IP1
20
IP1
8IP1 19
IP 1
15 IP1 6IP1 18 IP1 5IP114 IE 1
14 BT1 9
IP1
7
A
15 UL1
A
12 DSWP
A
7 LSW P
A
3 ACT±
A
4 ACT+
B
12 DS WH
A
5 TOA
1
SRLY25 13
2
31
2
31
IJ EA
2 1
PRND 2 L
146578 9
GR
R±B
L
G±W G
W
A/T INDICATOR SW
[NEUTRAL START SW AND BACK±UP LIGHT SW]
N1
2
3
FROM POWER SOYURCE SYSTEM
(
SEE PAGE 56 )
7. 5A
ST
P
N STARTER
RE LA Y
THEFT DETERRENT AND DOOR LOCK ECU
LOCK
UNLOCK
LOCK
UNLOCK
DOOR KEY LOCK AND
UNLOCK SW RH
DOOR LOCK MOTOR,
DOOR UNLOCK DETE CTION AND
DOOR OPEN DETECTION SW RH DOOR LOCK
CONTROL SW RHENGINE HOOD
COURTESY SW
LUGGAGE COMPARTMENT
DOOR OPENER MOTOR
G± Y G±L
R±B
L±W
L±R W±B
L±R L±R B
Y
W
B
L±O B
B
L±O
B
G±L L±R
G±L B
W±B W±B
L±R
W±B W±B W±B
W±B W±B
L±R R±BG±L
L±W
P±B
R±W G±W
G±Y G±Y
G±W
R±W P±B
L±W
R±BG±L L±W
P±B
R±W
G±W
L4 E5
D9
D11 D8
T8
,T
9
B A
M
1
IJ1
6
B±W
( A/T )
IJ28
B±W B
( M/T )(
M/T)
B±W
( A/T )
B±W
( M/T )
CLUTCH STA RT
SW (
M/T )
C23
( A/T )
B3 3
W±BW±B
WhereEverybodyKnowsYourName
Page 4072 of 4087

11 4
THEFT DETERRENT AND DOOR LOCK CONTROL
2
5
1K
71E 5
44 1I
71J 1
3 11 IE1
9
2
1
BM IF BL
BT1
8BT1 7IG1 2IJ1
4
IJ1
9
B
11
HORN B
4
SH B
8
PRLY A
8
+B 2
B
1 LUG
B
10 DS WL
A
9 IND
4
I72
12
1
4
3
3
15
10 1 2
BY1
8
IH FROM POWER SOURCE SYSTEM
(
SEE PAGE 56 )
25A
HAZ±HORN 30A
POWER30A
DOOR
POWER
MAIN
RELAY
W
WW W
G±R
WW
B±O
B±O
Y±RW±B
L±W
L±W
L±R
L±R
W±B W±B G±B
R±W L±G
L±G
R±W G±B
R
BR W±B
TRIP S W AND
THEFT DETERRENT
INDICATOR LIGHT
COMB INATION
METER
FUEL L I D
OPENER SOLENOID
FUEL LI D
OPENER SW
THEFT
DETERRENT
HORN
HORN
RELAY
LUGGAGE COMPARTMENT
LIGHT SW LUGGAGE COMPARTMENT
KEYUNLOCKSW
THEFT DETERRENT AND DOOR LOCK ECU T8
,T9 T1
F1 0
F1 4
T1 5
C14
L6 L5
B
A
B
6
52
31
WhereEverybodyKnowsYourName