Lexus SC300 / Lexus SC400. Manual — part 1019

117

: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS

CODE

SEE PAGE

JOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)

EB1

34

ENGINE WIRE AND ENGINE ROOM MAIN WIRE (FRONT SIDE OF R/B NO.2)

IE1

36

ENGINE ROOM MAIN WIRE AND COWL WIRE (R/B NO.4)

IF2

36

FRONT DOOR LH WIRE AND COWL WIRE (LEFT KICK PANEL)

IG1

36

INSTRUMENT PANEL WIRE AND COWL WIRE (R/B NO.5)

IJ1

36

ENGINE WIRE AND COWL WIRE (RIGHT KICK PANEL)

IJ2

36

ENGINE WIRE AND COWL WIRE (RIGHT KICK PANEL)

IP1

38

FRONT DOOR RH WIRE AND COWL WIRE (RIGHT KICK PANEL)

BT1

40

FLOOR WIRE AND COWL WIRE (LEFT KICK PANEL)

BY1

40

INSTRUMENT PANEL WIRE AND FLOOR NO.3 WIRE (RIGHT KICK PANEL)

: GROUND POINTS

CODE

SEE PAGE

GROUND POINTS LOCATION

EA

34

FRONT SIDE OF RIGHT FENDER

IF

36

LEFT KICK PANEL

IH

36

UNDER THE ASHTRAY LH

IJ

36

RIGHT KICK PANEL

BL

40

UNDER THE CENTER PILLAR RH

BM

40

BACK PANEL CENTER

: SPLICE POINTS

CODE

SEE PAGE

WIRE HARNESS WITH SPLICE POINTS

CODE

SEE PAGE

WIRE HARNESS WITH SPLICE POINTS

I 7

38

COWL WIRE

B 7

40

FRONT DOOR RH WIRE

I11

38

COWL WIRE

B33

40

FRONT DOOR RH WIRE

B 4

40

FRONT DOOR LH WIRE

10

TROUBLESHOOTING

VOLTAGE CHECK

(a)

Establish conditions in which voltage is present at the
check 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 no
voltage 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

Ω

/V

minimum) for troubleshooting of the electrical circuit.

11

FINDING A SHORT CIRCUIT

(a)

Remove the blown fuse and disconnect all loads of the
fuse.

(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 the

Relay) 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 unless
absolutely 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.

12

TROUBLESHOOTING

HOW TO REPLACE TERMINAL
(with terminal retainer or secondary locking
device)

1.

PREPARE THE SPECIAL TOOL
HINT: To remove the terminal from the connector, please

construct and use the special tool or like object shown
on the left.

2.

DISCONNECT CONNECTOR

3.

DISENGAGE THE SECONDARY LOCKING DEVICE OR
TERMINAL RETAINER
(a)

Locking device must be disengaged before the
terminal locking clip can be released and the terminal
removed from the connector.

(b)

Use a special tool or the terminal pick to unlock the
secondary locking device or terminal retainer.

NOTICE:
Do not remove the terminal retainer from connector
body.

For Non–Waterproof Type Connector
HINT: The needle insertion position varies according

to the connector’s shape (number of terminals
etc.), so check the position before inserting it.

“Case 1”

Raise the terminal retainer up to the temporary
lock position.

“Case 2”

Open the secondary locking device.