Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual - part 1168

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

W 

Minimum 
operating 
voltage:7V at 
25

°C (77°F) 

 

 
1T 
(MR5C) 
/Brown 

12V 
Approx. 90

W 

Minimum 
operating 
voltage: 10.5V 
at 25

°C (77°F) 

 

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

8-16  ELECTRICAL-BODY AND CHASSIS 

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