Toyota Wiring (1991-2005 year). Instruction - part 1

 
 
 

TOYOTA 

 

Wire Harness Repair Instruction 

 

1991 - 2005 

2002

All rights reserved. This book may not be
reproduced or copied, in whole or in part, without the
written permission of Toyota Motor Corporation.

FOREWORD

This manual has been prepared for use when
performing terminal repairs, wire repairs, or connector
repairs on vehicles.

A step–by–step section on connector repair and
terminal repair is included.

There is a section of charts with terminal and connector
illustrations, part numbers, and notes on terminal
removal.

By using this guide, a satisfactory repair of the wiring
harness and connectors in Toyota vehicles will be easy
to achieve.

All information in this manual is based on the latest
product information at the time of publication. However,
specifications and procedures are subject to change
without notice.

Tab width
0.64 mm

INTRODUCTION–GENERAL INFORMATION

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Wire Harness Repair Instruction (RM1022E)

GENERAL INFORMATION

This manual provides instruction in the following repairs:

How to Inspect for System Inspection

Circuit Protection

Terminal and Connector Repair Procedure

NOTICE:
When inspecting or repairing the SRS AIRBAG, be sure to carefully read the precautionary
instructions and procedure in the Repair Instruction for the applicable model.

After any electrical repair is made, always test the circuit by operating the devices in the circuit. This
confirms not only that the repair is correct, but also that the cause of the complaint was correctly
identified.

Terminal type number name

The terminal type number naming system has changed:
the metric system will be used in place of the inch system.
To be more specific, male tab width ”in millimeters” will be
used as terminal type number from now on –– in place of
male tab width in inches which has been in use so far.

Below is a table of comparison:

Old terminal type No.

(inch)

New terminal type No.

(mm)

025

→

0.64

040 (II, III, IV)

→

1.0 (II, III, IV)

050

→

1.3

070 (II)

→

1.8 (II)

090 (II)

→

2.3 (II)

187

→

4.8

250 (II)

→

6.3 (II)

305

→

7.7

312

→

8.0

375

→

9.5

For those connectors which are not shown above, the
terminal type numbers remain unchanged.

A

Terminal (Female)

Housing (Female)

Housing (Male)

Terminal (Male)

Wire
Harness
(W/H)

Electric Wire

Terminal

Housing

Fuse

Other

J/B
(Junction Block)

R/B
(Relay Block)

Insulator

Copper Wires
(Conductor)

B =

Black

W

=

White

L =

Blue

BR =

Brown

V =

Violet

SB =

Sky Blue

R =

Red

G

=

Green

P =

Pink

LG =

Light Green

Y =

Yellow

GR =

Gray

O =

Orange

A–2

INTRODUCTION–GENERAL INFORMATION

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Wire Harness Repair Instruction (RM1022E)

What is Wire Harness?

The wire harness (W/H) is systems of electric wires for
automobiles to connect all the electronics parts in
automobile electrically and work them. As more electronics
parts are introduced in automobiles recently, the electric
wires used for the wire harness are increasing in number
and the structure is becoming more complicated. As a
result of that, there are hundreds of connectors, which is
the parts which connects wires mechanically and
electrically, in one vehicle. Therefore, numbers of the
connector terminal (Terminal) or the connector housing
(Housing) are designed to meet many kinds of uses of
circuits. Various components have been improved to
ensure the product reliability or realize a wider space in the
vehicles.

Wire Harness Components

Wire harness mainly consists of wires, terminals, or
housings.
There are various components are designed for many
parts of vehicles, such as one with high heat–resistance,
water–resistance, or bending ability, ones have different
current capacities, or ones are hardly influenced by
electromagnetic noise.

Electric Wire

The electric wires used for the wire harness consists of the
conductor made from numbers of twisted mild copper wire
with a diameter of less than 0.5 mm and the insulator
surrounding the conductor.
The insulator is generally made from vinyl chloride and
covers the conductor with even thickness. The insulators
are color–coded in order to distinguish each wire. The base
colors or the stripe patterns is used to make difference
between insulators. Each color of wires is indicated by the
abbreviation in the repair manual and the electrical wiring
diagram.

A

L

Y

–

(Blue)

(Yellow)

Example: L–Y

Tab width
1.3 mm

Rubber 
Plug

Rubber Ring

Housing Lance
Type

Terminal Lance
Type

INTRODUCTION–GENERAL INFORMATION

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Wire Harness Repair Instruction (RM1022E)

The first letter indicates the basic wire color and the second
letter indicates the color of the stripe.

Terminal and housing

Terminal connects wires and housing insulates connecting
parts.
There are the male terminal and the female terminal.  The
types of terminals are decided by tab width of male
terminal. And the terminal with the rubber plug or the
rubber ring is used in the part, such as the engine
compartment, which become wet. For the circuit with slight
current at EFI system or ABS system, the gold–plated
terminal is introduced for ensuring reliabilities.
As the number of the circuit is increasing recently, there are
new types of parts introduced. For example, there is the
hybrid type housing, which is a combination of terminals
with different tab width, such as the power source terminal
or the signal terminal. Also, new type of connector such as
the double lock housing, which is designed with the
retainer in addition to the lance to prevent terminal from
slipping off, is available. The new type of connectors are
produced to realize higher product reliabilities and utilized
widely recently. The major characteristics of these new
connectors are shown in the table 1.
There are two types of lances: housing lance, which is
inside the housing and terminal lance, which is inside the
terminal.

A

A–4

INTRODUCTION–GENERAL INFORMATION

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Wire Harness Repair Instruction (RM1022E)

Table 1 : Characteristics of the new types of connector (Improvement)

Characteristics (Improvement)

Note

Retainer (Double Lock)

Lance (Primary Lock)

Housing

Terminal

1. Double Lock

If terminal is not inserted to
housing correctly, the retailer
does not fit.

2. Extension of Housing

Extension

Shortening

Housing

Terminal

This is to prevent deformation of
the terminal when it is inserted
diagonally.

3. Change of Contact Structure and

Introduction of Box–Shaped Structure

Expansion of contact section
Stabilization of contact pressure

4. Change of Locking Shape

Ribs are added

This improves the close fit of
locking and you can hear the
click sound and feel that the
connector is completely
installed.

A

To Ignition SW
IG Terminal

Fuse

Relay

SW2

Solenoid

Voltmeter

[A]

[B]

[C]

SW1

Ohmmeter

SW

INTRODUCTION–HOW TO PERFORM FOR SYSTEM INSPECTION

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Wire Harness Repair Instruction (RM1022E)

HOW TO PERFORM FOR SYSTEM INSPECTION

This inspection procedure 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

Always inspect the trouble taking the following items into consideration:

Ground point fault

Open or short circuit of the wire harness

Connector or terminal connection fault

Fuse or fusible link fault

NOTICE:

This is an on–vehicle inspection during system operation.
Therefore, inspect the trouble with due regard for safety.

If connecting the battery directly, be careful not to cause a short circuit, and select the applicable
voltage.

1.

Voltage Check

(a)

Establish conditions in which voltage is present at the
check point.

Example:
[A] – Ignition SW on
[B] – Ignition SW and SW 1 on
[C] – 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 bulb instead of a voltmeter.

2.

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.

A

Diode

Ohmmeter

Diode

Ohmmeter

Digital Type

Analog Type

Bulb

Ohmmeter

A–6

INTRODUCTION–HOW TO PERFORM FOR SYSTEM INSPECTION

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Wire Harness Repair Instruction (RM1022E)

If the circuit has diodes, reverse the two leads and check
again.
When touching the negative (–) lead to the diode positive
(+) side and the positive (+) lead to the negative (–) side,
there should be continuity. When touching the two leads in
reverse, there should be no continuity.

HINT:

Specifications may vary depending on the type of

tester, so refer to the tester’s instruction manual before
performing the inspection.

Check LED (Light Emitting Diode) in the same manner as
that for diodes.

HINT:

Use a tester with a power source of 3V or greater to
overcome the circuit resistance.

If a suitable tester is not available, apply battery
voltage and check that the LED lights up.

(c)

Use a volt/ohmmeter with high impedance (10k

Ω

/V

minimum) for troubleshooting of the electrical circuit.

3.

Bulb Check

(a)

Remove the bulb.

(b)

There should 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.

A