Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual - part 1478

8-12  ELECTRICAL-BODY AND CHASSIS

PARTS FOR ELECTRICAL CIRCUIT

WIRING

Wire Color

All wires have color-coded insulation.
Wires belonging to system's main harness will have a single
color.
Wires belonging to a system's sub-circuits will have a colored
stripe.
Striped wires use the following code to show wire size and
colors.
Example: 0.5 G / R

Red (Stripe color)

Green (Base color)

Wire size (0.5mm

2

)

Abbreviations are used to indicate wire color within a circuit
diagram.
Refer to the following table.

Wire Color-Coding

Color-Coding

Meaning

Color-Coding

Meaning

B

Black

BR

Brown

W

White

LG

Light green

R

Red

GR

Grey

G

Green

P

Pink

Y

Yellow

LB

Light blue

L

Blue

V

Violet

O

Orange

ELECTRICAL-BODY AND CHASSIS  8-13

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

Normal 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

8-14  ELECTRICAL-BODY AND CHASSIS

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

ELECTRICAL-BODY AND CHASSIS  8-15

CIRCUIT BREAKER

The circuit breaker is a protective device designed to open the
circuit when a current load is in excess of rated breaker
capacity.
If there is a short or other type of overload condition in the
circuit, the excessive current will open the circuit between the
circuit breaker terminals.
The reset knob pops out when the circuit is open.
Push the reset knob in place to restore the circuit after
repairing it.

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

1T

(MR5C)

/Black

12V

Approx. 90

Ω

Minimum

operating

voltage:7V at

25

°C (77°F)

1T

(MR5C)

/Brown

12V

Approx. 90

Ω

Minimum

operating

voltage: 10.5V

at 25

°C (77°F)

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