1995 ISUZU TROOPER Workshop Manual

Wire Size (Fig. 8-25)
Outside diameter
Fig. 8-25
Wire Size Table
----,
Cross sectional area
CHASSIS ELECTRICAL 8 -11
The size of wire used in a circuit is determined by the
amount of current (amperage), the length of the
circuit, and the voltage drop allowed. The following
wire size and load capacity, shown below, are
specified
by AWG (American Wire Gauge) (Nominal
size means approximate cross sectional area).
Nominal size Cross sectional
Outside diameter Allowable AWG size
area
(mm2 ) (mm)
0.3
0.5
0.85
1.25
2
3
5 8
15
20
FUSES
FUSE
0.372
0.563
0.885
1.287
2.091
3.296
5.227
7.952
13.36
20.61
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 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.
The
replacement fuse must have the same amperage
specification as the original 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 (Fig.
8-26). 1.5
1.7
1.9
2.2
2.7
3.6 4.4
5.5
7.0
8.2
current (A) (cross
reference)
9
22
12 20
16 18
21 16
28 14
37.5
12
53 10
67 8
75 6
97 4
Normal Blown
Fig.
8-26

8-12 CHASSIS ELECTRICAL
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
ofthe 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 (Fig. 8-27).
Fusible Link Specifications
Normal Blown
Fig.
8-27
Type Rating
Case Color Maximum Circuit Current (A)
Connector
30A Pink 15
Connector 40A Green 20
Bolted 50 A Red 25
Bolted 60A Yellow 30
Bolted
BOA Black 40
CIRCUIT BREAKER (Fig. 8-28)
Push
Fig. 8-28
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 (Fig. 8-29)
Fig. 8-29
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 G).
The installation of a relay between the battery and the
load reduces the voltage drop®.
Because the switch controls the relay, amperage
through the switch can be reduced.
..

CHASSIS ELECTRICAL 8-13
RELAY SPECIFICATIONS AND CONFIGURATIONS (Fig. 8-30)
Name/ Rated Name/ Rated
Color voltage/Coil
Internal circuit Color voltage/Coil Internal circuit
resistance resistance
12V/ 12V/
® ~1 Approx.
~
®u~
Approx.
~£:=!:~ 1M 80 2M 80
a(( (MRSL)/ Minimum Black
operating ® ... J Brown operating ::Q __ j
voltage: 7V voltage: 7V ® 4 at 77°F (2S°C) at 77"F (2SOC)
~
® 18
®tiT
18-1M
•
:E:t: : ... J
(MR5)/ i @ . . @
Grey Grey ®~ 4
1M
:@ff
i
®~
(MRS)/
rou~ Minimum
u~ Black i 0 @ . 1M operating ~ : 4
(Case), ® ... J ® 1
® J Blue voltage:
9V
(Base) @ at 68°F (20°C)
:@j
12V @®
1T
m
1M Minimum
'
m~
(MRS)/ t (MRSB)/ operating ~ : Black/ ' 0 @ voltage: @ u
Black
Blue ® 4.3V at 77°F
@® (2SOC)
1
12V/
1@ .ff
1M Minimum
(Horn operating ® 8V
at 68°F (20°C) @ .
* Relay contact shown in the wiring diagram indicates condition before actuation.
Fig.
8-30

8-14 CHASSIS ELECTRICAL
DIODE
DIODE SPECIFICATIONS AND CONFIGURATIONS (Fig. 8-31)
MARK/ [THERE SHOULD BE CONTINUITY IN l
SHAPE
CONSTRUCTION CHECKING EITHER A OR B WHEN A CIRCUIT
COLOR TESTER IS CONNECTED WITH
DIODE TERMINAL
~ [1r!Bf=5~
o--j)f--o
TERMINAL NO. 2 1
CONNECTION A @ e I PATTERN B e ~ BLACK I i !
[}
o------J>f----o TERMINAL
NO.
3 2 1
e ~ A c±l 8 CONNECTION
PATTERN B c±l e
BLACK e c±l
[
!i~~
~ u 3 TERMINAL NO.
3 2 1
pJr-qr u 2 e c±l I n 1 A CONNECTION c±l 8
~
PATTERN c±l e B (f) BLACK (~
2f 2f 2f
[i
TERMiiNAL NO. 4 3 2 1
·-·-·-·fl-4 c±l e
·-·-·-·#-3
A e c±l -·-· t=:-e c±l ·-·-·-·#-2 CONNECTION
PATTERN 8 ~ ·-·-·-·#-1
B l±l e I
BLACK I c±l e
Fig. 8-31
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-aooc
Storage temperature -40°C·-1 oooc
..