relay LEXUS SC400 1991 Service Repair Manual

10
TROUBLESHOOTING
VOLTAGE CHECK
(a) Establish conditions in which voltage is present at thecheck point.
Example: ± Ignition SW on
± Ignition SW and SW 1 on
± Ignition SW, SW 1 and Relay on (SW 2 off)
(b) Using a voltmeter, connect the negative lead to a good ground point or negative battery terminal, and the
positive lead to the connector or component terminal.
This check can be done with a test light instead of a
voltmeter.
CONTINUITY AND RESISTANCE CHECK
(a) Disconnect the battery terminal or wire so there is novoltage between the check points.
(b) Contact the two leads of an ohmmeter to each of the check points.
If the circuit has diodes, reverse the two leads and check
again.
When contacting the negative lead to the diode positive side
and the positive lead to the negative side, there should be
continuity.
When contacting the two leads in reverse, there should be no
continuity.
(c) Use the volt/ohmmeter with high impedance (10 k W/V
minimum) for troubleshooting of the electrical circuit.
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FINDING A SHORT CIRCUIT
(a) Remove the blown fuse and disconnect all loads of thefuse.
(b) Connect a test bulb in place of the fuse.
(c) Establish conditions in which the test bulb comes on.
Example: ± Ignition SW on
± Ignition SW and SW 1 on
± Ignition SW, SW 1 and Relay on (Connect theRelay) and SW 2 off (or Disconnect SW 2)
(d) Disconnect 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.
CAUTION:
(a) Do not open the cover or the case of the ECU unlessabsolutely necessary. (If the IC terminals are touched,
the IC may be destroyed by static electricity.)
(b) When replacing the internal mechanism (ECU part) of the digital meter, be careful that no part of your body or
clothing comes in contact with the terminals of leads
from the IC, etc. of the replacement part (spare part).
DISCONNECTION OF MALE AND FEMALE
CONNECTORS
To pull apart the connectors, pull on the connector itself, not the
wire harness.
HINT: Check to see what kind of connector you are disconnecting
before pulling apart.
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ABBREVIATIONS
DISCONNECTION AND CONNECTION OF BOLT
TYPE CONNECTORS
For engine and ECT ECU in this vehicle, connectors are used
which require a bolt built into the connector to be screwed down to
securely connect the connector.
1. Disconnect the connectorAfter completely loosening the bolt, the two parts of the
connector can be separated.
NOTICE:
Do not pull the wire harness when disconnecting the
connector.
2. Connect the connector
NOTICE:
Before connecting the connector, always check that the
terminals are not bent or damaged.
(a) Match the guide section of the male connectorcorrectly with the female connector, then press them
together.
(b) Tighten the bolt. Make sure the connectors are completely connected,
by tightening the bolt until there is a clearance of less
than 1 mm (0.04 in.) between the bottom of male
connector and the end of female connector.
ABBREVIATIONS
The following abbreviations are used in this manual.
A/C = Air Conditioning O/D = Overdrive
ABS = Anti±Lock Brake System R/B = Relay Block
A/T = Automatic Transmission RH = Right±Hand
CB = Circuit Breaker SRS = Supplement Restraint System
COMB. = Combination SW = Switch
ECT = Electronic Controlled Transmission TDCL = Total Diagnostic Communication Link
ECU = Electronic Control Unit TEMP. = Temperature
EGR = Exhaust Gas Recirculation TRAC = Traction Control
FL = Fusible Link VSV = Vacuum Switching Valve
ISC = Idle Speed Control W/ = With
J/B = Junction Block W/O = Without
LH = Left-Hand
* The titles given inside the components are the names of the terminals (ter\
minal codes) and are not treatedas being abbreviations.
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105
TURN SIGNAL FLASHER
(4) 3 ± GROUND: CHANGES FROM APPROX. 12 VOLTS TO 0 VOLTS WITH IGNITION SW ON AND TURN SIGNAL SW LEFT, OR WITH
HAZARD SW ON
(4) 5 ± GROUND: CHANGES FROM APPROX. 12 VOLTS TO 0 VOLTS WITH IGNITION SW ON AND TURN SIGNAL SW RIGHT, OR WITH
HAZARD SW ON
(4) 4 ± GROUND: CONTINUITY WITH TURN SIGNAL SW LEFT, OR HAZARD SW ON
(4) 2 ± GROUND: CONTINUITY WITH TURN SIGNAL SW RIGHT, OR HAZARD SW ON
(4) 1 ± GROUND: APPROX. 12 VOLTS WITH IGNITION SW ON OR HAZARD SW ON
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
C13A28F 726R1031
C14B28F 826R1131
C1628H 729
: RELAY BLOCKS
CODESEE PAGERELAY BLOCKS (RELAY BLOCK LOCATION)
219ENGINE COMPARTMENT LEFT
423LEFT KICK PANEL (J/B NO.1 LEFT)
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODESEE PAGEJUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)
1A20ENGINE ROOM MAIN WIRE
1C20FLOOR WIRE
1E20INSTRUMENT PANEL WIRE
1H
1J20COWL WIRE
1K
20COWL WIRE
3A
3D22INSTRUMENT PANEL WIRE
3G
: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS
CODESEE PAGEJOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)
IE136ENGINE ROOM MAIN WIRE AND COWL WIRE (R/B NO. 4)
IG136INSTRUMENT PANEL WIRE AND COWL WIRE (R/B NO 5)IG236INSTRUMENT PANEL WIRE AND COWL WIRE (R/B NO. 5)
IQ138INSTRUMENT PANEL WIRE AND CONSOLE BOX WIRE (UNDER THE INSTRUMENT PANEL CENTER)IQ238INSTRUMENT PANEL WIRE AND CONSOLE BOX WIRE (UNDER THE INSTRUMENT PA N E L CENTER)
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATION
EA34FRONT SIDE OF RIGHT FENDER
EB34FRONT SIDE OF LEFT FENDER
IF36LEFT KICK PANEL
BM40BACK PANEL CENTER
: SPLICE POINTS
CODESEE PAGEWIRE HARNESS WITH SPLICE POINTSCODESEE PAGEWIRE HARNESS WITH SPLICE POINTS
I 738COWL WIREB1540FLOOR MAIN WIRE
SERVICE HINTS
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184
UNLOCK AND SEAT BELT WARNING
1E
12
3A
4
3D
13
1B
5 2
B
1
A
7
1E 1
1H
13
1D
10
1J
1 1C
12 1D 8
1I
15
9
10
6 3
2
1
BK
IF 10A
DOME
10A
GAUGE
SEAT BELT
WARNING LIGHT
[COMB. METER]
INTEGATION RELAY
BUZZER TI M ER
UNLOCK
WARNING SW
[IGNITION SW] BUCKLE
SW LH
DOOR OPEN
DETECTION
SW LH
FROM POWER SOURCE SYSTEM
(
SEE PAGE 56 )
FROM POWER SOURCE SYSTEM(
SEE PAGE 56 )
C12 ,C 14
D10
B4
I15
R
R
Y
Y
W±B
W±B
W±B
Y
W±B
W±B
W±B W±B B±L B±L
R±W
W±B
W±B
V
86
5
10 179
AB
1 2
(W/ MEMORY )
( W/O MEMORY )
( W/ MEMORY )
( W/O MEMORY )
Ba1
14
Ba2
5 Ba2
6 Ba1
11
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185
CURRENT ALWAYS FLOWS TO TERMINAL 1 OF THE INTEGRATION RELAY THROUGH DOME FUSE.
1. SEAT BELT WARNING SYSTEM
WHEN THE IGNITION SW IS TURNED ON, CURRENT FLOWS FROM THE GAUGE FUSE TO TERMINAL 7 OF THE INTEGRATION RELAY.
AT THE SAME TIME, CURRENT FLOWS TO TERMINAL 9 OF THE RELAY FROM THE GAUGE FUSE THROUGH THE SEAT BELT
WARNING LIGHT. THIS CURRENT ACTIVATES THE INTEGRATION RELAY AND, FOR APPROX. 4±8 SECONDS, CURRENT FLOWING
THROUGH THE WARNING LIGHT FLOWS FROM TERMINAL 9 OF THE RELAY " TERMINAL 10 " GROUND, CAUSING THE WARNING
LIGHT TO LIGHT UP. AT THE SAME TIME AS THE WARNING LIGHT LIGHTS UP, A BUCKLE SW OFF SIGNAL IS INPUT TO TERMINAL 8
OF THE RELAY, THE CURRENT FLOWING TO TERMINAL 7 OF THE RELAY FLOWS FROM TERMINAL 10 " GROUND AND THE SEAT
BELT WARNING BUZZER SOUNDS FOR APPROX. 4±8 SECONDS. HOWEVER, IF THE SEAT BELT IS PUT ON DURING THIS PERIOD
(WHILE THE BUZZER IS SOUNDING), SIGNAL INPUT TO TERMINAL 8 OF RELAY STOPS AND THE CURRENT FLOW FROM TERMINAL 7
OF THE RELAY " TERMINAL 10 " GROUND IS CUT, CAUSING THE BUZZER TO STOP.
2. UNLOCK WARNING SYSTEM
WITH THE IGNITION KEY INSERTED IN THE KEY CYLINDER (UNLOCK SW ON), THE IGNITION SW STILL OFF AND \
DOOR OPEN (DOOR
COURTESY SW ON), WHEN A SIGNAL IS INPUT TO TERMINAL 6 OF THE RELAY, THE INTEGRATION RELAY OPERATES, CURRENT
FLOWS FROM TERMINAL 7 OF THE RELAY " TERMINAL 10 " GROUND AND UNLOCK WARNING BUZZER SOUNDS.
B 4 BUCKLE SW LH
1±2 : CLOSED WITH DRIVER'S LAP BELT IN USE
D10 DOOR COURTESY SW LH
3±6 : CLOSED WITH LH DOOR OPEN
I15 UNLOCK WARNING SW [IGNITION SW]
10±9: CLOSED WITH IGNITION KEY IN CYLINDER
INTEGRATION RELAY
10±GROUND: ALWAYS CONTINUITY6±GROUND: CONTINUITY WITH DRIVER'S DOOR OPEN
5±GROUND: CONTINUITY WITH IGNITION KEY IN CYLINDER
8±GROUND: CONTINUITY WITH DRIVER'S LAP BELT IN USA
9±GROUND: 0 VOLTS FOR 4±8 SECONDS WITH IGNITION SW ON AND APPROX. 12 VOLTS 4±8 SECONDS AFTER IGNITION SW ON
1±GROUND: ALWAYS APPROX. 12 VOLTS
: PARTS LOCATION
CODESEE PAGECODESEE PAGECODESEE PAGE
B 432C14B28I1529
C12A28D1030
: RELAY BLOCKS
CODESEE PAGERELAY BLOCKS (RELAY BLOCK LOCATION)
219ENGINE COMPARTMENT LEFT
: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR
CODESEE PAGEJUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)
1B20ENGINE ROOM MAIN WIRE
1C20FLOOR MAIN
1D20FRONT DOOR LH WIRE
1E20INSTRUMENT PANEL WIRE
1H
1I20COWL WIRE
1J
20COWL WIRE
3A22INSTRUMENT PANEL WIRE3D22INSTRUMENT PANEL WIRE
: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS
CODESEE PAGEJOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)
Ba142FLOOR WIRE AND FRONT SEAT LH WIRE (UNDER THE FRONT LH SEAT)Ba242FLOOR WIRE AND FRONT SEAT LH WIRE (UNDER THE FRONT LH SEAT)
: GROUND POINTS
CODESEE PAGEGROUND POINTS LOCATION
IF36LEFT KICK PANEL
BK40UNDER THE CENTER PILLAR LH
SYSTEM OUTLINE
SERVICE HINTS
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