TOYOTA SUPRA 1995 Service Repair Manual

Tab width
0.64 mm
INTRODUCTION±GENERAL INFORMATION
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Wire Harness Repair Manual (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 Manual 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 ºin millimetersº 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
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INTRODUCTION±GENERAL INFORMATION
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Wire Harness Repair Manual (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

LY±
(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 Manual (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

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INTRODUCTION±GENERAL INFORMATION
5
Wire Harness Repair Manual (RM1022E)
Table 1 : Characteristics of the new types of connector (Improvement)
Characteristics (Improvement)Note
Retainer (Double Lock)
Lance (Primary Lock)
Housing
Terminal
1. Double LockIf terminal is not inserted to
housing correctly, the retailer
does not fit.
2. Extension of Housing
Extension
ShorteningHousing
Terminal
This is to prevent deformation of
the terminal when it is inserted
diagonally.
3. Change of Contact Structure and
Introduction of Box±Shaped StructureExpansion of contact section
Stabilization of contact pressure
4. Change of Locking Shape
Ribs are addedThis 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 SolenoidVoltmeter [A]
[B]
[C] SW1
Ohmmeter
SW
INTRODUCTION±HOW TO PERFORM FOR SYSTEM INSPECTION
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Wire Harness Repair Manual (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
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INTRODUCTION±HOW TO PERFORM FOR SYSTEM INSPECTION
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Wire Harness Repair Manual (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 (10kW/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

Fuse Case Test Bulb
Short [A]
SW1
Short [B]
Relay
Light
Short [C]
SW2 SolenoidDisconnect
Disconnect DisconnectTo Ignition SW
IG Terminal
INTRODUCTION±HOW TO PERFORM FOR SYSTEM INSPECTION
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Wire Harness Repair Manual (RM1022E)
4. Finding a 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)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).
A

Push
Equal Amperage Rating
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INTRODUCTION±CIRCUIT PROTECTION
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Wire Harness Repair Manual (RM1022E)
CIRCUIT PROTECTION
All electrical circuits are protected against excessive loads which might occur because of shorts or
overloads in the wiring system. Such protection is provided by a fuse, circuit breaker, or fusible link, A
short circuit may cause a fuse to blow or a circuit breaker to open.
RESET CIRCUIT BREAKER
1. Remove Circuit Breaker
(a)Disconnect the negative (±) cable from the battery.
(b)Remove the circuit breaker.
2. Reset Circuit Breaker
(a)Insert the needle into the reset hole and push it.
(b)Using an ohmmeter, check that there is continuity
between both terminals of the circuit breaker.
If continuity is not as specified, replace the circuit breaker.
HINT: If replacing the circuit breaker, be sure to replace
it with a breaker with an equal amperage rating.
3. Install Circuit Breaker
(a)Install the circuit breaker.
(b)Connect the negative (±) cable to the battery.
HINT: If a circuit breaker continues to cut out, a short
circuit is indicated. Have the system checked by a qualified
technician.
A

Equal Amperage Rating
Equal Amperage Rating
Puller
INTRODUCTION±CIRCUIT PROTECTION
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Wire Harness Repair Manual (RM1022E)
REPLACEMENT OF FUSE AND FUSIBLE LINK
HINT: If replacing the fuse or fusible link, be sure to
replace it with a fuse or fusible link with an equal amperage
rating.
NOTICE:
1.Turn off all electrical components and the ignition
switch before replacing a fuse or fusible link. Do
not exceed the fuse or fusible link 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 or fusible link continues to blow, a short circuit is
indicated. The system must be checked by a qualified
technician.
HINT: The puller is located at Junction Block No.2.
A

Reference:
(mm)
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TERMINAL AND CONNECTOR REPAIR±PREPARATORY ITEMS
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Wire Harness Repair Manual (RM1022E)
PREPARATORY ITEMS
Crimping tool AMP Part No. 169060For caulking
press sleeves
ToolSpecial tool Refer to the following illustrationTo remove the
terminal
SST 09991±00500
To remove the
0.64 connector
terminal
GaugeCaliper 0±150 mm
To measure the
diameter of the
core
Others
82999±12010 (Red)
Press sleeve 82999±12020 (Blue)
82999±12030 (Yellow)
To connect wires
Others
Silicon tape 08231±00045
To waterproof
the connected
section
Special Tool
HINT: To remove the terminal from the connector, please
construct and use the special tool or like object shown on
the left.
Preparation of the SST to release the 0.64 connector terminal.
SST 09991±00500
HINT:
This is a SST for releasing terminals from 0.64 connectors.
B