1991 LEXUS SC400 Service Repair Manual

wheel android auto OBD port length sport mode water pump

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LEXUS SC400 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 INTEGRA

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
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Page 3946 of 4087

LEXUS SC400 1991 Service Repair Manual
11 0
LIGHT AUTO TURN OFF
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATION
IF36LEFT KICK PANEL
: SPLICE POINTS
CODESEE PAGEWIRE HARNESS WITH SPLICE POINTSCODESEE PAGEWIRE HARNESS WITH SPLICE POINTS

Page 3947 of 4087

LEXUS SC400 1991 Service Repair Manual
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 I

Page 3948 of 4087

LEXUS SC400 1991 Service Repair Manual
196
MOON ROOF
1B
5
1I
16
1K
71K 13 2
1D
8 1F
8
1H 10
IP1
20 IP1
15
BZ1
4
BZ1
5 BZ1
1
IJ IF B3
B1
6 3
6
3
M
R
Y±R
W±B
W±B
W±B
W±B
W±B L
R
L±W
B±R
R
Y±R
W±B
R±B
R±W
R±W
R±W
W±B
W±B
B
BR

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LEXUS SC400 1991 Service Repair Manual
197
1D
10 1J 11F61F 5
1I
7
BZ1
3
BZ1
8BZ1 7BZ12BZ1 6
4
W±B
W±B W±B W±B
Y±R Y±R
L±Y L±B L±R
L±W
V
P
V±W
P±L
W±B
W±B
W±B
L
R
1273 POWER MAIN
RELAY
MOON RO OF CO NTROL
RELAY
OPEN
CLOSE
DO

Page 3950 of 4087

LEXUS SC400 1991 Service Repair Manual
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 TURN

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
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LEXUS SC400 1991 Service Repair Manual
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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 CONTR

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
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LEXUS SC400 1991 Service Repair Manual
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MOON ROOF
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