Isuzu KB P190. Manual — part 1238

8A-14 ELECTRICAL-BODY AND CHASSIS

Distinction of Circuit by Wire Base Color

Base color

Circuits

Base color

Circuits

B

Starter circuit and grounding circuit

Y

Instrument circuit

W

Charging circuit

L, O, BR,

R

Lighting circuit

LG, GR,

Other circuits

G

Signal circuit

P, LB, V

Wire Size

Wire size is specified with the metric gauge system.
The metric gauge system gives the wire size in cross sectional
area measured in square millimeters.

Wire Size Specifications

Nominal size

Cross sectional area

(mm

2

)

Outside diameter

(mm)

Allowable current

(A)

0.3 0.372 1.8

9

0.5 0.563 2.0 12

0.85 0.885 2.2

16

1.25 1.287 2.5

21

2 2.091 2.9 28

3 3.296 3.6 37.5

5 5.227 4.4 53

8 7.952 5.5 67

15 13.36 7.0 75

20 20.61 8.2 97

ELECTRICAL-BODY AND CHASSIS 8A-15

Normal

Blown

FUSE

Fuses are the most common form of circuit protection used in
vehicle wiring.
A fuse is a thin piece of wire or strip of metal encased in a
glass or plastic housing.
It is wired in series with the circuit it protects.
When there is an overload of current in a circuit, such as a
short of a ground, the wire or metal strip is designed to burn
out and interrupt the flow of current.
This prevents a surge of high current from reaching and
damaging other components in the circuit.
Determine the cause of the overloaded before replacing the
fuse.
Never replace a blown fuse with a fuse of a different amperage
specification.
Doing so can result in an electrical fire or other serious circuit
damage.
A blown fuse is easily identified.

Normal

Blown

FUSIBLE LINK

The fusible link is primarily used to protect circuits where high
amounts of current flow and where is would not be practical to
use a fuse.
For example, the starter circuit.
When a current overload occurs, the fusible link melts open
and interrupts the flow of current so as to prevent the rest of
the wiring harness from burning.
Determine the cause of the overload before replacing the
fusible link.
The replacement fusible link must have the same amperage
specification as the original fusible link.
Never replace a blown fusible link with fusible link of a different
amperage specification.
Doing so can result in an electrical fire or other serious circuit
damage.
A blown fusible link is easily identified.

Fusible Link Specifications

Type

Rating

Case Color

Maximum Circuit Current (A)

Connector 30A

Pink

15

Connector 40A Green

20

Bolted 50A Red

25

Bolted 60A Yellow

30

Bolted 80A Black

40

8A-16 ELECTRICAL-BODY AND CHASSIS

RELAY

Battery and load location may require that a switch be placed
some distance from either component.
This means a longer wire and a higher voltage drop

1

. The

installation of a relay between the battery and the load reduces
the voltage drop

2

.

Because the switch controls the relay, amperage through the
switch can be reduced.

Relay Specifications and Configurations

Name/

Color

Rated

voltage/ Coil

resistance

Internal circuit

Name/

color

Rated

Voltage/Coil

resistance

Internal circuit

1T

(MICRO

ISO)

/Black

12V

Approx. 92

Ω

Minimum

operating

voltage: 7V at

20

°C (77°F)

1M (MINI

ISO)

/Black

12V Approx.

94

Ω Minimum

operating

voltage: 7V at

20

°C (77°F)

1M

(MICRO

ISO)

/Black

12V

Approx. 132-3
Ω Minimum
operating

voltage: 7V at

20

°C (77°F)

1M

(power)/

Black

12V Approx.

94

Ω Minimum

operating

voltage: 7V at

20

°C (77°F)

* Relay contact shown in the wiring diagram indicates condition before actuation.

ELECTRICAL-BODY AND CHASSIS 8A-17

DIODE

Diode Specifications and Configurations

SHAPE

MARK/

COLOR

CONSTRUCTION

CHECKING

THERE SHOULD BE CONTINUITY IN
EITHER A OR B WHEN A CIRCUIT
TESTER IS CONNECTED WITH
DIODE TERMINAL

BLACK

2

1

CONNECTION

A

+

-

PATTERN

B

-

+

TERMINAL NO.

BLACK

3

2

1

-

+

CONNECTION

+

-

PATTERN

+

-

-

+

B

A

TERMINAL NO.

BLACK

3

2

1

-

+

CONNECTION

+

-

PATTERN

+

-

-

+

B

A

TERMINAL NO.

BLACK

4

3

2

1

+

-

A

-

+

CONNECTION

-

+

PATTERN

-

+

B

+

-

+

-

TERMINAL NO.

Maximum Rating (Temp.=25

°°°°C)

Items

Rating

Remarks

Peak reverse voltage

400V

Transient peak reverse voltage

500V

Average output current

1.5A

Temp.=40

°C

Working ambient temperature

-30

°C∼80°C

Storage temperature

-40

°C∼100ßC