1991 LEXUS SC400 mirror

DEFOGGER SYSTEM
Description
The component parts of this system and their functions are described in the\
following table.
 Parts Name\
 \
Function
 Defogger\
 \
When over current flows in the defogger circuit, the Defogger fuse break\
s the circuit to pro-
tect it against damage.
 


Defogger Relay\
 
\

\

This relay is supplied with current from terminal IG1 of ignition switch\
(Ignition switch
ON) and switches large current from the defogger.
 


A/C Control Panel
Assembly

Defogger Switch\
 
\

\

The defogger switch is built into the A/C Control Panel Assembly. This switch is
supplied with current from the relay and fuse HTR. Grounds current from \
the defogger
relay, turning the defogger relay ON.
 




Defogger

Rear Window
 Outer Mirror\
 
\


\

\

These defoggers generate heat when current is supplied from the defogger\
relay.
Parts Location
±
BODY ELECTRICAL SYSTEM Lighting SystemBE±51
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(d) Place the voltmeter positive (+) lead against the defoggerpositive (+) terminal.
(e) Place the voltmeter negative (±) lead with the foil strip against
the heat wire at the positive (+) terminal end and slide it
toward the negative (±) terminal end.
(f) The point where the voltmeter deflects from zero to several volts is the place where the heat wire is broken.
HINT: IF the heat wire is not broken, the voltmeter indicates 0 volts
at the positive (+) end of the heat wire but gradually increases to
about 12 volts as the meter probe is moved to the other end.
2. REPAIR DEFOGGER WIRES (a) Clean the broken wire tips with a grease, wax andsilicone remover.
(b) Place the masking tape along both sides of the wire to be repaired.
(c) Thoroughly mix the repair agent (Dupont paste No. 4817).
(d) Using a fine tip brush, apply a small amount to the wire.
(e) After a few minutes, remove the masking tape.
(f) Allow the repair to stand at least 24 hours.
(Mirror Defogger)
REMOVAL AND INSTALLATION OF
MIRROR ASSEMBLY
(See Outside Rear View Mirror on Pub. No. RM260U2, page
BO±42)
BE±54
±
BODY ELECTRICAL SYSTEM Defogger System
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INSPECTION OF MIRROR DEFOGGER
INSPECT MIRROR DEFOGGER
(a) Connect the positive (+) lead from the battery to terminal 7 (4)
and the negative (±) lead to terminal 8 (5).
(b) Check that the mirror becomes warm. HINT: It will take a short time for the mirror to become warm.
If the mirror does not become warm, replace the mirror as-
sembly.
( ): w/o Driving Position Memory
Troubleshooting
You will find the cause of trouble more easily using the table shown belo\
w. In this table, the number indicate
the order priority of the causes in trouble. Check each part in the order s\
hown. If necessary, replace the parts.

Refer to 1992 LEXUS SC300 Repair Manual (Pub. No. RM260U2)
See pageBE±4 , 20
BE±4 , 20
BE±4 , 22
BE±172
BE±173
BE±173
BE±174
±
BODY ELECTRICAL SYSTEM Defogger SystemBE±55
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LOCATION OF PLASTIC BODY PARTS
Outside Rear View Mirror (ABS)
Instrument Panel Safety Pad (PVC/PUR) Rear Spoiler (SMC)
Front Turn Signal Light (PC/PP)
Center Stop Light (PC)
Mead Light (PC/PP)
Head Light (PC/PP)
Front Bumper Extension
Mounting Bracket (PP)
Quarter Panel
Mud Guard (TPO)
Outside Moulding
Front Fender Mud Guard (TPO)
Front Spoiler (PUR) Cowl Top Ventilation Louver (PP)
Front Bumper Cover (PUR) Side Turn Signal Light (PMMA/ABS)
Cornering Light (PC)
HINT:
wResin material differs with model.
/ Made up of 2 or more kinds of materials.
PLASTIC BODY PARTSPP-4
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Steering Wheel Pad (Airbag and Inflator)
Junction Block No. 1 Center Airbag
Front Airbag Sensor
Front Airbag Sensor
Warning Light Spiral Cable (in Combination Switch)
HANDLING PRECAUTIONS ON RELATED COMPONENTS
1. SRS AIRBAG
Locations of Airbag Components
This vehicle has an SRS AIRBAG (referred to as the airbag in the remain\
der of this manual).
When handling airbag components (removal, installation or inspection, e\
tc.), always follow the directions
given in the repair manual for the relevant model year to prevent the oc\
currence of accidents and airbag
malfunction.
Also take the following precautions when repairing the body:

Work must be started after 20 seconds or longer from the time the ignitio\
n switch is set to the LOCK
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 w\
ork is started within 20 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
memory system. Then when work is finished, reset the clock and audio sys\
tems as before.
When the vehicle has tilt and telescopic steering, power seat, and outsi\
de rear view mirror, which are all
equipped with memory function, it is not possible to make a record of th\
e 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 back-up powe\
r supply from outside
the vehicle.

When using electric welding, first disconnect the airbag connector (yel\
low color and 2 pins) under the
steering column near the combination switch connector before starting wo\
rk.
Sensor Assembly
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Shift Lock ECU
Tilt and Power
Telescopic ECU
Airbag ECU
Cruise Control ECU Engine ECUABS and Traction ECU
(w/ Traction System) or
ABS ECU
(w/o Traction System)
Theft Deterrent and
Door Lock ECU
(w/ Traction System)
Traction ECU
Remote Control Mirror ECU A/C Control Amplifier
PPS ECU
Engine Cooling Fan ECU
Component to be aligned
Section of repair manual
for relevant model year
Front Wheels Suspension and Axle (SA) section
Rear Wheels Suspension and Axle (SA) section
Propeller Shaft Propeller Shaft (PR) section
2. BRAKE SYSTEM
The brake system is one of the most important safety components. Always \
follow the directions and
notes given in section BR of the repair manual for the relevant model ye\
ar when handling brake sys-
tem parts.
NOTICE: When repairing the brake master cylinder or TRAC system, bleed t\
he air out of the TRAC
system.
3. DRIVE TRAIN AND CHASSIS
The drive train and chassis are components that can have great effects on the running performance
and vibration resistance of the vehicle. After installing components in \
the sections listed in the table
below, perform alignments to ensure correct mounting angles and dimensions. P\
articularly accurate
repair of the body must also be done to ensure correct alignment.
HINT: Correct procedures and special tools are required for alignment. Alway\
s follow the directionsgiven in the repair manual for the relevant model year during alignment \
and section DI of this manual.
4. ECU (ELECTRONIC CONTROL UNIT)
Locations of ECUs
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Fuel Pump ECUAuto Antenna Motor and Relay
Power Seat ECU
(For Passenger's Seat)
Power Seat ECU
(For Driver's Seat) CD Automatic Changer
Wireless Door Lock ECU
Moon Roof Control Relay
Locations of ECUs (Cont'd)
Many ECUs are mounted in this vehicle.
Take the following precautions during body repair to prevent damage to th\
e ECUs.


Before starting electric welding operations, disconnect the negative (-\
) terminal cable from the battery.
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
memory system. Then when work is finished, reset the clock and audio sys\
tems as before.
When the vehicle has tilt and telescopic steering, power seat and outsid\
e rear view mirror, which are all
equipped with memory function, it is not possible to make a record of th\
e 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.

Do not expose the ECUs to ambient temperatures above 80 °C (176 °F).
NOTICE: If it is possible the ambient temperature may reach 80°C (176°F) or, more, remove the ECUs
from the vehicle before starting work.

Be careful not to drop the ECUs and not to apply physical shocks to them\
.
5. COMPONENTS ADJACENT TO THE BODY PANELS
Various types of component parts are mounted directly on or adjacently to\
the body panels.
Strictly observe the following precautions to prevent damaging these com\
ponents and the body panels
during handling.

Before repairing the body panels, remove their adjacent components or ap\
ply protective covers over
the components.

Before prying components off using a screwdriver or a scraper, etc., attach protective tape to the tool
tip or blade to prevent damaging the components and the body paint.

Before removing components from the outer surface of the body, attach protective tape to the body to
ensure no damage to painted areas.
HINT: Apply touch-up paint to any damaged paint surfaces.

Before drilling or cutting sections, make sure that there are no wires, \
hoses, etc., on the reverse side.
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PREPARATION
EG0AZ±0A
RECOMMENDED TOOLS
MA009±02
EQUIPMENT
\
 
\

\
Dial indicator with magnetic base 


\
 \
Micrometer
\
 
\

\
MirrorBrake hose
\
 
\

\

Steel square
\
 \
Thermometer
\
 
\

\
Torque wrench
\
 \
Vernier calipers
MA00B±02
COOLANT 
Item
 
Capacity
 
Classification 

Engine coolant (w/ Heater)10.8 liters (11.4 US qts, 9.5 lmp. qts)Ethylene±glycol base
MA00D±0E
LUBRICANT
 Item Capacity Classification 

Engine oil (Drain and refill)
w/ Oil filter change
/ Oil filt h
 

4.8 liters (5.1 US qts, 4.2 lmp. qts)
 

API grade SG or SH, Energy±Conserving II
or ILSAC multigrade, and recommended
 


g
w/o Oil filter change 


4.8 liters (5.1 US qts, 4.2 lm. qts)
4.5 liters (4.8 US qts, 4.0 lmp. qts) 


or ILSAC multigrade, and recommended
viscosity oil with SAE 5W±30 being pre-
ferred engine oil
 Brake fluid Ð SAE J1703 or FMVSS No.116 DOT3
 Automatic transmission fluid 1.9 liters (2.0 US qts, 1.7 lmp. qts) ATF TYPE T±II

Automatic transmission fluid
(Drain and refill)
1.9 liters (2.0 US qts, 1.7 lm . qts)

AT F TYPE TII
 




Differential oil 




1.35 liters (1.43 US qts, 1.19 lmp. qts) 




Hypoid gear oil API GL±5
Above±18
5C (0 5F): SAE 90
Below±18 5C (0 5F): SAE 80W±90 or 80W
±
MAINTENANCE (1UZ ± FE)MA±5
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