fuse LEXUS SC300 1991 Service Owner's Manual

(b) Press the mirror switch and check if the mirrors surfacerepeatedly becomes ºbrightº and ºdarkº.
If operation is not as specified, replace the liquid crystal inner
mirror.
(Circuit)
Disconnect the inner mirror connector and inspect the con-
nector on the wire harness side as shown.
Check forTester connectionConditionSpecified value
Voltage2±GroundConstantBattery voltage
Continuity1 GroundIgnition key setContinuityContinuity1±GroundIgnition key removedNo continuity
If circuit is not as specified, refer to BE±165 wiring diagram
and inspect the circuits connected to other parts.
(Key Unlock Warning Switch)
(See page BE±26)
Troubleshooting
You will find the cause of trouble more easily by properly using the table \
shown below. In this table, the numbers
indicate the order of priority of the cruses of trouble. Check each part in the \
order shown. If necessary, replace
the part.
See pageBE±4,21BE±165BE±26 ±±
TroubleParts
name
DOME FuseLiquid Crystal Inner MirrorKey Unlock Warning SwitchWire Harness
Liquid Crystal Inner Mirror does not operate.1234
BE±166±
BODY ELECTRICAL SYSTEM Liquid Crystal Inner Mirror System
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Troubleshooting
You will find the cause of trouble more easily properly using the table sho\
wn below. In this table, the numbers
indicate the order priority of the causes of trouble. Check each part in the order shown. If necessary, replace
the part.
See pageBE±4,20BE±168BE±169 ±±
TroubleParts
name
GAUGE FuseTension Reducer SolenoidBuckle SwitchWire Harness
Tension Reducer does not operate.
(Driver's and Passenger's)12
Tension Reducer does not operate. (Only one side)213
BE±170±
BODY ELECTRICAL SYSTEM Electric Tension Reducer System
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DEFOGGER SYSTEM
Description
The component parts of this system and their functions are described in the\
following table.
Parts NameFunction
DefoggerWhen over current flows in the defogger circuit, the Defogger fuse break\
s the circuit
to protect it against damage.
Defogger RelayThis 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 SwitchThe 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 MirrorThese defoggers generate heat when current is supplied from the defogger\
relay.
Parts Location
±
BODY ELECTRICAL SYSTEM Defogger SystemBE±171
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INSPECTION OF MIRROR DEFOGGER
INSPECT MIRROR DEFOGGER(a) Connect the positive (+) lead from the battery to terminal
7 and the negative (±) lead to terminal 8.
(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.
Troubleshooting
You will find the cause of trouble more easily using the table shown below. 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.
See pageBE±4 ,20BE±4,20BE±4,22BE±172BE±173 ±±BE±173 ±±BE±174
TroubleParts
name
HEATER FuseMIR±HTR FuseDEFOG FuseDefogger SwitchDefogger RelayWire HarnessDefogger WiresCKE CoilMirror Defogger
All defogger systems do not operate.11234
Rear window defogger does not operate.312
Mirror Defogger does not operate.132
±
BODY ELECTRICAL SYSTEM Defogger SystemBE±175
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SLIDING ROOF SYSTEM
Description
Standby Operation

Current flows from the DOME fuse to terminal A1 of the sliding roof control rel\
ay (hereafter called
relay).

When the ignition switch is ON, the current flows from the power window relay to terminal A3 of the
relay.
Operation
Roof Position
Function Fully
Open Fully
Closed
Momentary
Stop
Limit
Switch
No. 1
Limit
Switch
No. 2
Sliding
Roof
Control
Switch Down
Up
Sliding Period Idling Period
CLOSE DOWN OPEN
UP ON
ON OFF
OFF
Tilting
Period
2. OPEN operation
When the switch on the ºOPENº side of the control switch is pushed, co\
ntinuity is produced between termi-
nal A8 of the relay and body ground. Then the relay operates, the curren\
t flows through terminal A3 of the
relay
terminal B3
terminal 1 of the sliding roof motor
terminal 3
terminal B1 of the relay
terminal
A5
the body ground, and the motor starts to run in order to open the slidi\
ng roof.
3. CLOSE operation
When the switch on the ºCLOSEº side of the control switch is pushed, c\
ontinuity is produced between termi-
nal A7 of the relay and body ground. Then the relay operates, the current f\
lows through terminal A3 of the
relay
terminal B1
terminal 3 of the sliding roof motor
terminal 1
terminal B3 of the relay
terminal
A5
the body ground, and the motor starts to run in order to close the slid\
ing roof.
Momentary Stop
When the sliding roof reaches about 200 mm (7.87 in.) short of the fully closed position, the limit \
switch
is turned from ON to OFF, so there is not continuity between terminal B1 of the relay and body g\
round No.
1. As a result, the sliding roof stops at that position.
4. TILT UP operation
When the switch on the ºUPº side of the control switch is pushed, cont\
inuity is produced between terminal
A6 of the relay and body ground. Then the relay operates, the current flow\
s through terminal A3 of the relay

terminal B1
terminal 3 of the sliding roof motor
terminal 1
terminal B3 of the relay
terminal
A5
the body ground, and the motor starts to run in order to tilt up the sl\
iding roof.
5. TILT DOWN operation When the switch on the ºDOWNº side of the control switch is pushed, co\
ntinuity is produced between termi-
nal A2 of the relay and body ground. Then the relay operates, the current f\
lows through terminal A3 of the
relay
terminal B3
terminal 1 of the sliding roof motor
terminal 3
terminal B1 of the relay
terminal
A5
the body ground, and the motor starts to run in order to tilt down the \
sliding roof.
BE±176
±
BODY ELECTRICAL SYSTEM Sliding Roof System
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Troubleshooting
You will find the cause of trouble more easily by properly using the tabl\
e shown below. In this table, the numbers
indicate the order of priority of the causes of trouble. Check each part in the \
order shown. If necessary, replace
the part.
See page
BE±4,21BE±4,21BE±4,20BE±4,20BE±156BE±152BE±180BE±179BE±179 ±±BE±181BE±26BE±79BE±4,20 ±±
Part
name
Trouble
AM1 FuseDOME FuseDOOR FusePOWER FuseTheft Deterrent and Door Lock Control ECUPower Window Main RelaySliding Roof Control RelaySliding Roof SwitchSliding Roof MotorSliding Rood Motor (Stones to foreign material
trapped in motor assembly)Limit SwitchIgnition SwitchDoor Courtesy SwitchECU±IG FuseWire Harness
*1 Sliding roof system does not operate.1234
*2 Sliding roof system does not operate.35467892110
Sliding roof system operates abnormally.1324
Sliding roof system stops operation half way.1342
Buzzer does not sound.123
Buzzer sounds abnormally.1
ªKey±off Sliding Roofº operation does not
operate.124536
*1: Door Lock does not operate
*2: Door Lock is normal
BE±182
±
BODY ELECTRICAL SYSTEM Sliding Roof System
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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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Troubleshooting
You will find the cause of trouble more easily by properly using the table \
shown below. In this table, the
numbers indicate the order of priority of the causes of trouble. Check each part in \
the order shown. If neces-
sary, replace the part.
See pageBE±4 ,20BE±4,21BE±186BE±186 ±±BE±188SR±60 ±±IN±32BE±187
TroubleParts
name
RADIO NO. 2 FuseDOME FuseMirror SwitchMirror MotorWire HarnessMirror ECUDriving Position SwitchDriving Position Switch
(Position is not set)Tilt and Telescopic ECUMirror Sensors
Mirror does not operate.112354
Mirror operates abnormally1243
Mirror does not return to the memorized position.
(w/ Memory System)642135
Mirror returns to a position which is not memorized.
(w/ Memory System)312
BE±190±
BODY ELECTRICAL SYSTEM Power Mirror Control System
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Troubleshooting
You will find the cause of trouble more easily by properly using the tabl\
e shown below. In this table, the numbers
indicate the order or priority of the causes of trouble. Check each part\
in the order shown. If necessary, replace
the part.
See page
BE ± 4, 20BE ± 192BE ± 192
±
Trouble
Part Name
DOOR FuseFuel Lid Opener Switch
Mirror SwitchFuel Lid Opener SolenoidWire Harness
Fuel lid opener system does not operate1234
±
BODY ELECTRICAL SYSTEM Fuel Lid Opener SystemBE±193
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CLOCK
Troubleshooting
HINT: Troubleshoot the clock according to the table below.
Clock will not operate1
Clock loses or gains time2
1CLOCK WILL NOT OPERATE
(a) Check that the battery voltage is 10±16 V.
If voltage is not as specified, replace the battery.
(b) Check that the DOME fuse is not blown.
If the fuse is blown, replace the fuse and check for short.
(c) Troubleshoot the clock as follows.
HINT: Inspect the connector on the wire harness side.
BE±194
±
BODY ELECTRICAL SYSTEM Clock
Is there battery voltage between terminal
+B and body ground?
Is there continuity between terminal GND
and body ground?
Replace clock. Open or
short circuit in wire harness between
terminal +B and DOME fuse.
Open circuit in wire harness between
terminal GND and body ground.
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