fuses LEXUS SC400 1991 Service Repair Manual

5. Non±reusable parts(a) Always replace cotter pins, gaskets, O±rings and oilseals etc. with new ones.
(b) Non±reusable parts are indicated in the component
illustrations by the º º symbol.
6. Precoated parts Precoated parts are bolts and nuts, etc. that are coated with
a seal lock adhesive at the factory.
(a) If a precoated part is retightened, loosened or causedto move in any way, it must be recoated with the
specified adhesive.
(b) Recoating of precoated parts
(1) Clean off the old adhesive from the bolt, nut or threads.
(2) Dry with compressed air.
(3) Apply the specified seal lock adhesive to the bolt or nut threads.
(c) P re co a te d pa rts are in d ica te d in th e co m ponent
illustrations by the º
º symbol.
7. When necessary, use a sealer on gaskets to prevent leaks.
8. Carefully observe all specifications for bolt tightening
torques. Always use a torque wrench.
9. Use of special service tools (SST) and special service materials (SSM) may be required, depending on the nature
of the repair. Be sure to use SST and SSM where specified
and follow the proper work procedure. A list of SST and SSM
can be found in the preparation part at the front of each
section in this manual.
10. When replacing fuses, be sure the new fuse has the correct
amperage rating. DO NOT exceed the rating or use one with
a lower rating.
11. Care must be taken when jacking up and supporting the vehicle. Be sure to lift and support the vehicle at the proper
locations (See page IN±33).
(a) If the vehicle is to be jacked up only at the front or rear end, be sure to block the wheels at the opposite end in
order to ensure safety.
(b) After the vehicle is jacked up, be sure to support it on
stands. It is extremely dangerous to do any work on a
vehicle raised on a jack alone, even for a small job that
can be finished quickly.
±
INTRODUCTION General Repair InstructionsIN±5
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POWER MIRROR CONTROL
SYSTEM
Description
The Power Miror Control System carries out mirror left/right and up/down ad\
justments electrically when the Mir-
ror Switch is operated. In addition, operation of the Driving Position M\
emory and Return Switches makes it pos-
sible to store the adjusted position in memory and reproduce each adjustment \
when desired. The component
parts of this system and their functions are described in the following table\
.
Parts NameFunction
Outside Rear View
Mirror ECUThe Outside Rear View Mirror ECU is supplied with power from the DOME and RADIO
NO.2 fuses and is connected to the Tilt and Telescopic ECU, Mirror Switch, each
mirror motor and ground.
Rear View Adjustment
SwitchOperation of this switch sends left/right, up/down signals to Outside Re\
ar View Mirror
ECU.
Driving Position Memory
and Return SwitchesMemory and return signals are sent to the ECU via the Tilt and Telescopic ECU.
Mirror MotorThese motors operate on current from the Outside Rear View Mirror ECU, moving
the various parts of the mirror directly.
These sensors send signals about the motor positions to the ECU for stor\
ing in memory
and during return operation.
Left/Right Select SwitchThis switch is used to select operation of the Rear View Adjustment Switch for the
leftor right hand side mirror.
±
BODY ELECTRICAL SYSTEM Power Mirror Control SystemBE±183
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1RadioRADIO NOT OPERATING WHEN POWER
SWITCH TURNED TO ºONº.
A. Without CD player type
Does radio operate normally when AM or FM
button is pushed?
Check if RADIO NO.1 and RADIO NO.2 fuses
are OK.Is there battery voltage between the following
terminals with connector connected?

Radio receiver assembly A3±ground

Radio receiver assembly A4±ground
Is there continuity between the following termi-
nals with connector disconnected?

Radio receiver assembly A11±ground Radio receiver assembly faulty.Wire harness faulty
Wire Harness faulty.
Replace fuse.
Inspect power switch. Wire harness faulty.
Is there continuity between the following terminals
with connector disconnected?


Radio receiver assembly B2±power switch 12

Radio receiver assembly B4±power switch 11
Wire Harness faulty.
Is there battery voltage between the following
terminals with connector connected?


Radio receiver assembly A11±Power
amplifier A11
Is there continuity between the following termi-
nals with connector disconnected?

Power amplifier B7±ground
Power amplifier faulty.
BE±220±
BODY ELECTRICAL SYSTEM AUDIO SYSTEM
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B. with CD player type
Does radio operate normally when AM or FM
button is pushed?
Is there battery positive voltage between the
following terminals with connector connected?

Radio receiver assembly A3±ground

Radio receiver assembly A4±ground
Check if RADIO No.1 and RADIO No.2 fuses are OK.
Is therecontinuity between the following termi-
nals with connector disconnected?

Radio receiver assembly A11±ground Replace fuse.
Wire harness faulty
Radio receiver assembly faulty.
Wire harness faulty.
Wire harness faulty. Inspect power switch.
Wire harness faulty
Is there continuity voltage between the following
terminals with connector connected?


Radio receiver assembly B2±Power switch 12

Radio receiver assembly B3±Power switch 11
Is there continuity between the following terminals
with connector disconnected?

Radio receiver assembly A11±power amplifier A11
Is there continuity between the following terminals
with connector disconnected?

Radio receiver assembly B7±ground
Power amplifier faulty.
±
BODY ELECTRICAL SYSTEM AUDIO SYSTEMBE±221
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11Tape playerCASSETTE TAPE CANNOT BE INSERTED
A. without CD player type
Wire harness faulty. Radio receiver assembly faulty.
Is there continuity between the following terminals
with connector connected?

Radio receiver amplifier A3 ± ground

Radio receiver amplifier A4 ± ground
Radio receiver assembly faulty.
Is there continuity between the following terminals
with connector disconnected?


Radio receiver assembly A7 ± ground Replace fuse.
Wire harness faulty.Remove foreign object.
Is there a foreign object inside tape player?
Is radio operating normally?
Check if RADIO No. 1 and RADIO No. 2 fuses
are OK.
BE±234±
BODY ELECTRICAL SYSTEM AUDIO SYSTEM
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B. with CD player type
Wire harness faulty. Radio receiver assembly faulty.
Is there continuity between the following terminals
with connector connected?

Radio receiver amplifier A3 ± ground

Radio receiver amplifier A4 ± ground
Power amplifier faulty. Is there continuity between the following terminals
with connector disconnected?


Radio receiver assembly A11 ± ground Replace fuse.
Wire harness faulty.
Remove foreign object.
Is there a foreign object inside tape player?
Is radio operating normally?
Check if RADIO No.1 and RADIO No.2 fuses are OK
Wire harness faulty.Radio receiver assembly faulty.
Is there continuity between the following terminals
with connector disconnected?

Radio receiver assembly A11 ± Power amplifier A11
Is there continuity between the following terminals
with connector disconnected?

Power amplifier B7±ground.
±
BODY ELECTRICAL SYSTEM AUDIO SYSTEMBE±235
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12Tape playerCASSETTE TAPE WILL NOT EJECT
A. without CD player type
Is there battery voltage between the following ter-
minals with connector connected?

Radio receiver amplifier A3 ± ground

Radio receiver amplifier A4 ± ground Replace fuse.
Wire harness faulty.
Wire harness faulty.
Is radio operating normally?
Check if RADIO No.1 and RADIO NO.2 fuses are OK Is tape player operating normally?
Radio receiver assembly faulty
Is there continuity between the following terminals
with connector disconnected?


Radio receiver amplifier A7 ± ground Cassette tape is
jammed or radio receiv-
er assembly faulty.
Radio receiver assem-
bly faulty.
BE±236±
BODY ELECTRICAL SYSTEM AUDIO SYSTEM
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B. with CD player
Is there battery voltage between the following ter-
minals with connector connected?

Radio receiver amplifier A3 ± ground

Radio receiver amplifier A4 ± ground Replace fuse.
Wire harness faulty.
Is radio operating normally?
Check if RADIO No.1 and RADIO NO.2 fuses are OK Is tape player operating normally?
Power amplifier faulty.
Is there continuity between the following terminals
with connector disconnected?


Radio receiver amplifier A11 ± ground Cassette tape is
jammed or radio receiv-
er assembly faulty.
Radio receiver assem-
bly faulty.
Wire harness faulty. Wire harness faulty.Radio receiver assembly faulty.
Is there continuity between the following terminals
with connector disconnected?

Radio receiver amplifier A11 ± Power amplifier A11
Is there continuity between the following terminals
with connector disconnected?

Power amplifier B7 ± ground
±
BODY ELECTRICAL SYSTEM AUDIO SYSTEMBE±237
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32AntennaANTENNA±RELATED
Does antenna extend when radio switched ON?Wire harness faulty.
Is there battery voltage between the following
terminals with connector disconnected?


Motor antenna control relay 6 ± ground

Motor antenna control relay 14 ± ground

Motor antenna control relay 3 ± ground
Wire harness faulty.Replace fuses.
Radio receiver assembly faulty.
Check if ECU±IG, RADIO No. 1 and RADIO No.
2 fuse are OK.
ªAMº button turned ON.
Is there battery voltage between the following
terminals with connector connected?

Radio receiver assembly A9 (*A1) ± ground

Radio receiver assembly A8 ± ground

Radio receiver assembly D4 ± ground

Radio receiver assembly D10 ± ground Radio receiver side
faulty.
Motor antenna faulty.
Temporarily install another motor antenna is
radio operating normally?
Glass printed antenna faulty.
Check if glass printed antenna is OK.
Is there continuity between the following terminals
with connector disconnected?

Motor antenna control relay 4 ± ground
Continued on next page.
BE±260±
BODY ELECTRICAL SYSTEM AUDIO SYSTEM
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Description
The power source supplies power to each of the vehicle's electrical devices. It is composed of the battery, fuses
and relays, which are located centrally at relay block No. 2 and relay block No. 6 i\
n the engine compartment
and junction block No. 1 relay block No. 4 and relay block No. 5 in the \
cabin near the driver's feet.
Related systems for each Fuse
No.Part NameRelated Systems or Parts
1IGN
Charging System
AIR±BAG System1IGN
Engine
2ST
Starter
3WIPER
Wiper and Washer System
4HTR
Defogger System
A/C System
5ENGINE
Charging System
6RADIO NO. 2
Audio System
Power Mirror System

Cigarette Lighter
A/C System
7CIG
Combination Meter System
AIR±BAG System7CIG
Shift Lock System
Theft Deterrent System

TEL System
8STOP
Stop Light System
Cruise Control System
9TURN
Turn Signal and Hazard
Warning Light System
Cornnering Light System
10MIR HTR
Mirror Heater System
11PANEL
Illumination Light System
12ECU±B
Combination Meter System
AIR±BAG System

Combination Meter System
ECT System
13GAUGE
Back±Up Light
Transmission Indicator

Light Failare Sensor
ABS and TRAC

Power Seat System
Door Lock Control System

TEL System
Shift Lock System
14ECU±IG
Radiator Fan
Auto Antenna

Electric Tension Reducer System
Power Steering

Auto±Tilt away Steering
Cruise Control System
15TAIL
Taillight System
Side Marker15TAIL
Clearance Light
16DOOR
Power Seat System
Luggage Door Opener16DOOR
Door Lock Control System
Fuel Lid Opener System
17IG SWUpstream of ECU±IG, ENGINE, WIP, HTR, TURN, GAUGE, and ST Fuse
18PWR
Power Window System
Sliding Roof System
19ABS NO. 1
ABS and TRAC
20AM1Upstream of MIR HTR, TAIL, PANEL, STOP, ECUA±B, DOOR and PWR Fuse
21ALTUpstream of DEF, HTR, AM1, and ABS No. 1 Fuse
BE±18±
BODY ELECTRICAL SYSTEM Power Source
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