ignition switch LEXUS SC400 1991 Service Manual Online

INSPECTION OF THEFT DETERRENT
AND DOOR LOCK CONTROL ECU
INSPECT THEFT DETERRENT AND DOOR LOCK CONTROL
ECU(Circuit)
(a) Inspect ECU Power Source Circuit.(See page BE±376)
(b) Inspect Actuator Power Source Circuit.
(See page BE±378)
(c) Inspect Ignition Switch Circuit. (See page BE±25)
(d) Inspect Door Open Detection Switch Circuit.
(See page BE±392)
If circuit is as specified, inspect ECU operation.
(Operation)
(a) With the connectors connected, shut all doors.
(b) Check that there is 10 V ~ 14 V between terminal B8 and
ground when the ignition switch is turned on.
(c) After turning the ignition switch off, check within 60 seconds that there is battery voltage between terminal
B8 and ground.
(d) Turn the ignition switch on then off, and check that there
is 10 V ~ 14 V between terminal B8 and ground when the
ignition is switched off.
(e) Open the front door within 60 seconds of turning the
ignition off and check that there is no voltage between
terminal B8 and ground.
(f) Close all the doors and turn the ignition switch on.
(g) When a front door is opened, check that there is battery voltage between terminal B8 and ground.
(h) Check that there is no voltage between terminal B8 and ground when the ignition switch is turned to off.
If operation is not as specified, replace the ECU.
BE±156
±
BODY ELECTRICAL SYSTEM Power Window Control System
WhereEverybodyKnowsYourName

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 page
BE±4 ,21BE±4,21BE±4,20BE±4,20BE±156BE±152BE±149BE±151BE±152BE±26BE±392BE±4,20 ±±
Part
name
Trouble
AM1 FuseDOME FuseDOOR FusePOWER FuseTheft Deterrent and Door Lock Control ECUPower Window Main RelayPower Window Master SwitchPower Window SwitchPower Window MotorIgnition SwitchDoor Open Detection SwitchECU±IG FuseWire Harness
*1 Power window does not operate.1234
*2 Power window does not operate.35467218
ªOne Touch Power Window Systemº does
not operate.1
Only one window glass does not move.1234
ªWindow Lock Systemº does not operate1
ªWindow Lock Illuminationº does not light
up.1
Key±off power window does not operate124536
*1: Dook Lock does not operate.
*2: Dook Lock is normal.
±
BODY ELECTRICAL SYSTEM Power Window Control SystemBE±157
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(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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Parts Inspection
(Tension Reducer Solenoid)
REMOVAL AND INSTALLATION OF
TENSION REDUCER SOLENOID
(See page BO±71)
INSPECTION OF TENSION REDUCER
SOLENOID
INSPECT TENSION REDUCER SOLENOID
(Operation)
(a) Connect the positive (+) lead from the battery to terminal
2, and negative (±) lead to terminal 1.
(b) Pull the belt upward and check that the belt is slowly retracted when released.
(c) Disconnect the lead from the battery.
(d) Pull the belt upward and check that the belt is retracted
more quickly when released than in (b).
HINT: Do not tilt the retractor.
If the operation is not as specified, replace the front seat outer
belt assembly.
(Circuit)
Disconnect the tension reducer solenoid connector and in-
spect the connector on wire harness side as shown.
Check forTester connectionConditionSpecified value
Voltage2±GroundIgnition switchONBattery voltagegg
positionACC or LOCKNo voltage
Continuity1±GroundBuckle switch positionON (belt fastened)Continuityy
OFF (belt unfastened)No continuity
If the circuit is specified, replace the front seat outer belt as-
sembly.
If the circuit is not as specified, refer to BE±167 wiring dia-
gram, and inspect the circuits connected to other parts.
BE±168
±
BODY ELECTRICAL SYSTEM Electric Tension Reducer System
WhereEverybodyKnowsYourName

(Buckle Switch)
REMOVAL AND INSTALLATION OF
BUCKLE SWITCH
1. REMOVE BUCKLE SWITCH(a) Remove the driver or front passenger's seat.
(b) Disconnect buckle switch connector.
(c) Remove seat belt inner with buckle switch.
2. INSTALL BUCKLE SWITCH For installation follow the removal procedure in reverse.
INSPECTION OF BUCKLE SWITCH
INSPECT BUCKLE SWITCH(Switch Continuity)
(a) Check that there is continuity between terminals on theswitch side connector with the switch ON (belt
fastened).
(b) Check that there is no continuity between terminals on the switch side connector with the switch OFF (belt
unfastened).
If operation is not as specified, replace the seat belt inner.
(Switch Circuit)
Disconnect the connector from switch and inspect the con-
nector on wire harness side as shown.
Check forTester connectionConditionSpecified value
Voltage2±GroundIgnition switch posi-ONBattery voltagegg
tionACC or LOCKNo voltage
Continuity1±GroundConstantContinuity
If the circuit is not as specified, refer to BE±167 wiring dia-
gram, and inspect the circuits connected to other parts.
±
BODY ELECTRICAL SYSTEM Electric Tension Reducer SystemBE±169
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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
WhereEverybodyKnowsYourName

(c) Turn the defogger switch ON and check that the testbulb and indicator light turn ON, then turn OFF after
about 15 minutes.
If operation is not as specified, replace the air conditioner
control panel assembly.
(Defogger Relay)
INSPECTION OF DEFOGGER RELAY
INSPECT RELAY CONTINUITY AND OPERATION
Terminal
ConditionConstant
Apple battery voltage to terminals 1 and 3.
If continuity is not as specified, replace the relay.
(Defogger Wires)
INSPECTION AND REPAIR OF
DEFOGGER WIRES
1. INSPECT DEFOGGER WIRES
NOTICE:
w VWhen cleaning the glass, use a soft, dry cloth, and wipe
the glass in the direction of the wire. Take care not to
damage the wires.
w VDo not use detergents or glass cleaners with abrasive
ingredients.
w VWhen measuring voltage, wind a piece of tin foil around
the top of the negative probe and press the foil against
the wire with your finger as shown.
(a) Turn the ignition switch ON.
(b) Turn the defogger switch ON.
(c) Inspect the voltage at the center of each heat wire as
shown.
VoltageCriteria
Approx. 5 VOkay (No break in wire)
Approx. 10 V or 0 VBroken wire
HINT: If there is approximately 10 volts, the wire is broken be-
tween the center of the wire and the positive (+) end. If there
is no voltage, the wire is broken between the center of the
wire and ground.
±
BODY ELECTRICAL SYSTEM Defogger SystemBE±173
WhereEverybodyKnowsYourName

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
WhereEverybodyKnowsYourName

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
±
BODY ELECTRICAL SYSTEM Sliding Roof SystemBE±177
WhereEverybodyKnowsYourName

(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
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