LEXUS SC400 1991 Service Repair Manual

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
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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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6. TILT UP REMINDER SYSTEMIf the ignition switch is turned from ON to OFF or ACC and the sliding roof rem\
ains tilted up, after 60 seconds
have elapsed or either the driver or passenger door is opened, a buzzer will\
sound for approx. 8 seconds
as a reminder that the sliding roof is tilted up.
Parts Location
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BODY ELECTRICAL SYSTEM Sliding Roof SystemBE±177
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Wiring and Connector Diagrams
BE±178±
BODY ELECTRICAL SYSTEM Sliding Roof System
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Parts Inspection
(Power Window Main Relay)
INSPECTION OF POWER WINDOW MAIN
RELAY
(See Power Window Main Relay on page BE±152)
(Sliding Roof Switch)
REMOVAL AND INSTALLATION OF
SLIDING ROOF SWITCH
(See Sliding Roof on page BO±85)
INSPECTION OF SLIDING ROOF SWITCH
INSPECT SWITCH CONTINUITY
Terminal
Switch position
SLIDE
TILT OFF
OPEN
CLOSE
OFFUP
DOWN
If continuity is not as specified, replace the switch.
(Sliding Roof Motor)
REMOVAL AND INSTALLATION OF
MOTOR
(See Sliding Roof on page
BO±85)
INSPECTION OF MOTOR
INSPECT MOTOR OPERATION
(a) Disconnect the connector which has 3 terminals andinspect on the clamped connector side.
(b) Connect the positive (+) lead from the battery to terminal
1 and negative (±) lead to terminal 3 and check that the
motor turns clockwise.
(c) Connect the positive (+) lead from the battery to terminal
3 and negative (±) lead to terminal 1 and check that the
motor turns counterclockwise.
If operation is not as specified, replace the motor.
(d) Connect the connector.
±
BODY ELECTRICAL SYSTEM Sliding Roof SysytemBE±179
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(Sliding Roof Control Relay)
REMOVAL AND INSTALLATION OF
SLIDING ROOF CONTROL RELAY
(See Sliding Roof on page BO±85)
INSPECTION OF SLIDING ROOF
CONTROL RELAY
INSPECT CONTROL RELAY CIRCUIT
Disconnect the connector from the relay and inspect the con-
nector on the wire harness side as shown in the chart.
Check forTest connectionConditionSpecified value
ContinuityA2 ± GroundSliding roof control OFF or UPNo continuityyg
switch position (TILT)DOWNContinuity
A6 ± GroundSliding roof control OFF or DOWNNo continuityg
switch position (TILT)UPContinuity
A7 ± GroundSliding roof control OFF or OPENNo continuityg
switch position (SLIDE)CLOSEContinuity
A8 ± GroundSliding roof control OFF or CLOSENo continuityg
switch position (SLIDE)OPENContinuity
B1 ± GroundConstantNo continuity
B1 ± B3ConstantContinuity
B2 ± GroundNo. 1 limit switch
p
osition
OFF (Sliding roof tilt up or
approx. 200 mm (7.87 in.)
opened)No continuity
positionON (Except for conditions
mentioned above)Continuity
B3 ± GroundConstantNo continuity
B4 ± GroundConstantContinuity
B5 ± GroundConstantContinuity
B6 ± GroundNo. 2 limit switch OFF (Sliding roof closed)No continuity
positionON (Sliding roof opened)Continuity
VoltageA1 ± GroundConstantBattery voltageg
A3 ± GroundIgnition switch positionLOCK or ACC ( * )No voltageg
ONBattery voltage
(*) Except within 60 seconds after turning the ignition key to the OFF\
position and both the driver's door and
the passenger's door are closed. If circuit is as specified, replace the relay.
BE±180
±
BODY ELECTRICAL SYSTEM Sliding Roof System
WhereEverybodyKnowsYourName

(Sliding Roof Limit Switch)
REMOVAL AND INSTALLATION OF LIMIT
SWITCH
(See Sliding Roof on page BO±85)
INSPECTION OF LIMIT SWITCH
1. INSPECT LIMIT SWITCH CIRCUIT
Terminal
Switch position
OFF (SW pin released)
OFF (SW pin released) ON (SW pin pushed in)
ON (SW pin pushed in)
No. 1 limit
switch
No. 2 limit
switch
If continuity is not as specified, replace the switch.
2. INSPECT MOTOR WIRE CIRCUIT (a) Check that there is continuity between terminals A1 andB3.
(b) Check that there is continuity between terminals A2 and B4.
(c) Check that there is continuity between terminals A3 and B1.
If continuity is not as specified, replace the switch.
(Theft Deterrent and Door Lock Control
ECU)
(See page BE±155)
(Door Courtesy Switch)
(See page BE±79)
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BODY ELECTRICAL SYSTEM Sliding Roof SystemBE±181
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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
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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.
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BODY ELECTRICAL SYSTEM Power Mirror Control SystemBE±183
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Parts Location
BE±184±
BODY ELECTRICAL SYSTEM Power Mirror Control System
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