fuse LEXUS SC300 1991 Service Workshop Manual

WIRING DIAGRAM
NGOK
*1 The power source is supplied to the actuator(Slide motor) through the passenger's seat
ECU accordingly, if a short circuit of the W/H
or actuator occurs in the actuator circuit, the
DOOR fusible link may become OPEN, so
also inspect the actuator.
(Slide motor circuit on page BE±328).
OKNG
INSPECTION PROCEDURE
1Check voltage between terminals SLDF, SLDR, of ECU connector and body ground.
C
OK
PRemove ECU with connector still connected.
Measure voltage between SLDF, SLDR terminal and
body ground, when slide switch is operated.
Switch condition Voltage (V)
SLDF SLDR
Forward
Back 10 ± 14 V Below 1 V
Below 1 V 10 ± 14 V
Proceed to next circuit inspection shown on matrix chart
(See page BE±319).
2Check DOOR fuse.
Check for short in all the harness and components con-
nected to the DOOR fuse and repair them (See attached
wiring diagram). *1
Go to step [3].
±
BODY ELECTRICAL SYSTEM Power Seat Control System (Passenger's Seat)BE±335
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Check DOME fuse.NG OKCheck for short in all the harness
and components connected to the
DOME fuse (See attached wiring
diagram).1
Check and repair harness and connector
between ECU and battery. Proceed to next circuit inspection
shown on matrix chart (See page
BE±371
).
Repair or replace harness or
connector.
Check voltage between terminals +B1
and E of ECU connector.
Check for open in harness and connector
between ECU and body ground (See page
IN±27 ).
OK
OK
NG
NG
2
3
WIRING DIAGRAM
CIRCUIT INSPECTION
ECU Power Source Circuit
CIRCUIT DESCRIPTION
This circuit provides power to operate the theft deterrent and door lock ECU\
.
DIAGNOSTIC CHART
BE±376±
BODY ELECTRICAL SYSTEM Door Lock Control System
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OKNG
NGOK
OKNG
INSPECTION PROCEDURE
1Check DOME fuse.
C
OK
PRemove DOME fuse from R/B No. 2.
Check continuity of DOME fuse.
Continuity
Check for short in all the harness and components con-
nected to the DOME fuse (See attached wiring diagram).
2Check voltage between terminals +B1 and E of ECU connector.
C
OK
P1. Remove the No. 1 under cover and heater duct.
2. Disconnect the theft deterrent and door lock ECUconnectors.
Measure voltage between terminals +B1 and E of ECU
connector.
Voltage: 10 ± 14 V
Proceed to next circuit inspection shown on matrix chart
(See page BE±371).
3Check for open in harness and connector between ECU and body ground (Se\
e page IN±27).
Repair or replace harness or connector.
Check and repair harness and connector between
ECU and battery.
±
BODY ELECTRICAL SYSTEM Door Lock Control SystemBE±377
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NGOK
NG
OK
1
2
Check P/W fuse.
Check voltage between terminal +B2 of
ECU connector and body ground.
Check and repair harness and connectors
between ECU and battery
(See page IN±27). Check for short in all the harness
and components connected to the
DOOR fuse (See attached wiring
diagram).
*1
Proceed to next circuit inspection
shown on matrix chart (See page
BE±371
).
WIRING DIAGRAM
*1: The power source is supplied to the actuator
(door lock motor, luggage compartment door
opener motor) through the theft deterrent and
door lock ECU. Accordingly, if a short circuit of
the W/H or actuator occurs in the actuator circuit,
the DOOR fuse may become OPEN. so also in-
spect the actuator (door lock motor circuit on
page BE±380 , and the luggage compartment
door opener motor circuit on page BE±382).
Actuator Power Source Circuit
CIRCUIT DESCRIPTION
This circuit provides power to drive the door lock motor and the luggage com\
partment door opener mo-
tor.
DIAGNOSTIC CHART
BE±378±
BODY ELECTRICAL SYSTEM Door Lock Control System
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OKNG
NGOK
*1: The power source is supplied to the actuator (doorlock motor, luggage compartment door opener mo-
tor) through the theft deterrent and door lock ECU.
Accordingly, if a short circuit of the W/H or actuator
occurs in the actuator circuit, the DOOR fusible link
may become OPEN, so also inspect the actuator
(door lock motor circuit on page BE±380, and the
luggage compartment door opener motor circuit on
page BE±382 ).
INSPECTION PROCEDURE
1Check DOOR fuse.
C
OK
P1. Remove the No. 1 under cover and LH lower pad.
2. Remove the DOOR fusible link from J/B No. 1.
Check continuity of DOOR fuse.
Continuity
Check for short in all the harness and components con-
nected to the DPPR fusible link (See attached wiring dia-
gram). *1
2Check voltage between terminal +B2 of ECU connector and body ground.
C
OK
P1. Remove No. 1 under cover and heater duct.
2. Disconnect the theft deterrent and door lock ECU connector.
Measure voltage between terminal +B2 of ECU connec-
tor and body ground.
Voltage: 10 ± 14 V
Proceed to next circuit inpsection shown on matrix chart
(See page BE±371).
Check and repair harness and connectors be-
tween ECU and battery (See page IN±27).
±
BODY ELECTRICAL SYSTEM Door Lock Control SystemBE±379
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WIRING DIAGRAM
Check DOME fuse.NG
OK Check for short in all the harness
and components connected to
DOME fuse.
(See attached wiring diagram)
Check voltage between terminals +B and
E of wireless door lock ECU connector.
Check for open in harness and connector
between terminal E of ECU and body
ground (See page IN±27).
Check and repair harness and connector
between ECU and main switch, main
switch and battery. Check wireless door lock main switch. Proceed to next circuit inspec-
tion shown on matrix chart
(See page
BE±454).
Repair or replace harness or
connector.
Replace wireless door lock main
switch.
NG
NG
NG
OK
OK OK1
2
3
4
CIRCUIT INSPECTION
ECU Power Source Circuit
CIRCUIT DESCRIPTION
When the wireless door lock main switch is ON, battery voltage is applied to\
terminal +B of the
wireless door lock ECU, causing the ECU to operate.
When the wireless door lock main switch is OFF, battery voltage is not applied to terminal +B and the
ECU does not operate.
DIAGNOSTIC CHART
BE±460±
BODY ELECTRICAL SYSTEM Wireless Door Lock Control System
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OKNG
NGOK
OKNG
OKNG
INSPECTION PROCEDURE
1Check DOME fuse.
Check for short in all the harness and components con-
nected to DOME fuse (See attached wiring diagram).
2Check voltage between terminals +B and E of ECU connector.
C
OK
P1. Remove the rear seat and RH quarter trim panel.
2. Remove the ECU.
Measure voltage between terminals +B and E of ECU
connector, when wireless door lock main switch is on
and off.
Wireless door lock main switchON
OFF Voltage
10 ± 14 V
Below 1 V
Proceed to
next circuit inspection shown on matrix chart
(See page BE±454).
3Check for open in harness and connector between terminal E of ECU and bo\
dy ground
(See page IN±27).
Repair or replace harness or connector.
4Check wireless door lock main switch.
C
OK
P1. Remove the instrument lower finish panel.
2. Remove wireless door lock main switch.
3. Disconnect the connector.
Measure resistance between terminals of wireless door
lock main switch connector, when main switch is on and
off.
Wireless door lock main switch
ON
OFF Resistance
Continuity
1M or higher
Replace wireless door lock main switch.
Check and repair harness and connector between
ECU and main switch, main switch and battery.
±
BODY ELECTRICAL SYSTEM Wireless Door Lock Control SystemBE±461
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Replacement of Fuse
HINT: If replacing the fuse, be sure to replace it with a fuse
with an equal amperage rating.
NOTICE:
1. Turn off all electrical components and the ignition switchbefore replacing a fuse. Do not exceed the fuse amperage
rating.
2. Always use a fuse puller for removing and inserting a fuse. Remove and insert straight in and out without
twisting. Twisting could force open the terminals too
much, resulting in a bad connection.
If a fuse continues to blow, a short circuit is indicated. The
system must be checked by a qualified technician.
HINT: The puller is located at Relay Block No. 2.
How to Inspect for System Inspection
This inspection precedure is a simple troubleshooting which
should be carried out on the vehicle during system operation
and is based on the assumption of system component
trouble (except for the wires and connectors, etc.).
Always inspect the trouble taking the following items into con-
sideration.
wGround point fault
w Open or short circuit of the wire harness
w Connector or terminal connection fault
w Fuse or fusible link fault
NOTICE:
1. This is an on±vehicle inspection during system
operation. Therefore, inspect the trouble with due regard
for safety.
2. If connecting the battery directly, be careful not to short circuit, and select the applicable voltage.
BE±4±
BODY ELECTRICAL SYSTEM General Information
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(c) Use a volt/ohmmeter with high impedance (10 k/Vminimum) for troubleshooting of the electrical circuit.
Check the Bulb
(a) Remove the bulb.
(b) There s hould be continuity between the respective
terminals of the bulb together with a certain amount of
resistance.
(c) Apply the two leads of the ohmmeter to each of the terminals.
(d) Apply battery voltage and check that the bulb light up.
Check for Short Circuit
(a) Remove the blown fuse and eliminate all loads from the fuse.
(b) Connect a test bulb in place of the fuse.
(c) Establish conditions in which the test bulb comes on.
Example:
(A)±Ignition SW on
(B)±Ignition SW and SW 1 on
(C)±Ignition SW, SW 1 and Relay on (Connect the Relay) and
SW 2 off (or Disconnect SW 2)
(d) D i s c onnect and reconnect the connectors while
watching the test bulb. The short lies between the
connector where the test bulb stays lit and the connector
where the bulb goes out.
(e) Find the exact location of the short by lightly shaking the problem wire along the body.
BE±6
±
BODY ELECTRICAL SYSTEM General Information
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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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