1991 LEXUS SC400 wiring

OVERALL ELECTRICAL WIRING DIAGRAM
1234
23 LEXUS SC300(
Cont ' d )
5Ba2
BK
M
21
12
7W± B W± B L
L±B
P1 7
POWER SEAT MOTOR
( for Driver' s Seat
Si de Con t ro l )FRONT
REAR
SL I DE
Under the center
pillar LH
4Ba2
L±W
L±W
FRONT VERTICALUPP1 3
POWER SEAT MOTOR
(
for Driver' s Seat
Front Ver tical Cont rol )L±Y
DOWN
L±R
M
21
56 REAR VERTI CAL
UPP15
POWER SEAT MOTOR
(
for Rear Vert ical
Control )Y±G
DOWN
Y±L
M
21
98 LUMBAR SUPPORT
RE L EA SEP1 4
POWER SEAT MOTOR
(
for Driver' s Seat
Lumbar Support Control )G±R
PUSH
G
M
21
10 12
3
4 RE CL I NI NG
FRONTP16
POWER SEAT MOTOR
(
for Reclining
Motor Cont rol )Y±R
REAR
Y±B
M
21 11
P8
POWER SEAT CONTROL SW
(
for Driver' s Seat )
1C
8
1B
2
4
6
L±W
W± L
W
30A
DOOR
BATTERY100A AM1
120A ALT
F9
FUSE BLOCK
6
5
Power Seat
(
w/o Driving Positiotn Memory )
Power Source
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242
HOW TO READ THIS SECTION
OVERALL ELECTRICAL WIRING DIAGRAM
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Junction Block (the number in the circle is the
J/B No. and connector code is shown beside
it). Junction Blocks are shaded to clearly
separate them from other parts (different
junction blocks are shaded differently for fur-
ther clarification.).
Example:
Indicates related system.
Indicates the wiring harness and wiring har-
ness connector. The wiring harness with male
terminal is shown with arrows
Outside numerals are pin numbers.
is used to indicate different wiring and
connector, etc. when the vehicle model, engine
type, or specification is different.
Indicates a shielder cable.
Indicates and located on ground point.
The same code occuring on the next page
indicates that the wire harness is continuous.
System Title
Indicates the wiring color.
Wire colors are indicated by an alphabetical
code.
B = Black L = Blue R = Red
BR = Brown LG = Light Green V = Violet
G = Green O = Orange W = White
GR = Gray P = Pink Y = Yellow
The first letter indicates the basic wire color and the
second letter indicates the color of the stripe.
Indicates the connector to be connected to a
part (the numeral indicates the pin No.)
The position of the parts. is the same as shown
in the wiring diagram and wire routing.
Indicates the pin number of the connector.
The numbering system is different for female
and male connectors.
The numbering system for the overall wiring
diagram is the same as above.
Indicates a Relay Block. No Shading is used
and only the Relay Block No. is shown to distin-
guish it from the J/B.
243
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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
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177
SRS AIRBAG
NOTICE: When inspecting or repairing the SRS AIRBAG, perform the operation in accord\
ance with the
following precautionary instructions and the procedure and precautions in the Repair Manual for the applicable
model year.

Malfunction symptoms of the airbag system are difficult to confirm, so the diagnostic codes become the most
important source of information when troubleshooting.
When troubleshooting the airbag system, always inspect the diagnostic codes before disconnecting the
battery.

Work must be started after 30 seconds or longer from the time the Ignition SW is set to the ªLOCKº position
and the negative (±) terminal cable is disconnected from the battery.
(The airbag system is equipped with a back±up power source so that if work is started within 30 seconds of
disconnecting the negative (±) terminal cable of the battery, the airbag may be deployed.)
When the negative (±) terminal cable is disconnected from the battery, memory of the clock and audio systems
will be cancelled. So before starting work, make a record of the contents memorized by each me\
mory system.
Then when work is finished, reset the clock and audio system as before.
When the vehicle has tilt and telescopic steering, power seat, outside r\
ear view mirror and power shoulder
belt anchorage, which are all equipped with memory function, it is not possible to make a record of the memory
contents. So when the operation is finished, it will be necessary to explain this\
fact to the customer, and
request the customer to adjust the features and reset the memory.
To avoid erasing the memory of each memory system, never use a back±up \
power supply from outside the
vehicle.

When removing the steering wheel pad or handling a new steering wheel pad, keep the pad upper surfa\
ce
facing upward. Also, lock the lock lever of the twin lock type connector\
at the rear of the pad and take care
not to damage the connector.
(Storing the pad with its metallic surface up may lead to a serious accident if \
the airbag inflates for some
reason).

Store the steering wheel pad where the ambient temperature remains below\
93 °C (200 °F), without high
humidity and away from electrical noise.

Never use airbag parts from another vehicle. When replacing airbag parts\
, replace them with new parts.

Never disassemble or repair the steering wheel pad, center airbag sensor asse\
mbly or front airbag sensors.

Before repairing the body, remove the airbag sensors if during repair shocks are likely to be app\
lied to the
sensors due to vibration of the body or direct tapping with tools or oth\
er parts.

Do not reuse a steering wheel pad or front airbag sensors.
After evaluating whether the center airbag sensor assembly is damaged or not, decide whether or not to reuse
it. (See the Repair Manual for the method for evaluating the center airbag\
sensor assembly.)

When troubleshooting the airbag system, use a high±impedance (Min. 1\
0k W/V) tester.

The vehicle wiring harness exclusively for the airbag system is distinguish\
ed by corrugated yellow tubing, as
are the connectors.

Do not measure the resistance of the airbag squib.
(It is possible this will deploy the airbag and is very dangerous.)

If the wire harness used in the airbag system is damaged, replace the wh\
ole wire harness assembly.
When the connector to the airbag front sensors can be repaired alone (when \
there is no damage to the wire
harness), use the repair wire specially designed for the purpose.
(Refer to the Repair Manual for the applicable Model year for details o\
f the replacement method.)

INFORMATION LABELS (NOTICES) are attached to the periphery of the airbag componen\
ts. Follow the
instructions on the notices.
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