Mitsubishi Montero Sport (2004+). Manual — part 403

HOW TO DIAGNOSE

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GENERAL <ELECTRICAL>

00E-9

CHECKING SWITCHES

M1001004800144

In a circuit diagram, a switch is shown in the idle state.
1. Normally open or normally closed switch

Switches are classified into those which open the circuit and
those which close the circuit when off.
Switches are shown in their normal state unless specified
otherwise.

2. Switch connection

This figure illustrates a complex switch. The continuity
between terminals at each position is as indicated in the
table below.

SWITCH
POSITION

TESTER
CONNECTION

SPECIFIED
CONNECTION

OFF

−

−

1st stage

1

−5−6

Continuity

2nd stage

1

−4−6

Continuity

3rd stage

1

−3−6

Continuity

4th stage

1

−2−6

Continuity

ACX00944AC

CURRENT
FLOWS

CURRENT DOES
NOT FLOW

CURRENT DOES
NOT FLOW

CURRENT FLOWS

OFF

OFF

ON

ON

NORMALLY OPEN (NO) TYPE

NORMALLY CLOSED (NC) TYPE

ACX00945 AB

6

OFF

5

4

3

2

1

1ST 2ND 3RD 4TH STAGE

HOW TO DIAGNOSE

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GENERAL <ELECTRICAL>

00E-10

CHECKING RELAYS

M1001004900130

1. Relays may be classified as the normally open-type or the

normally closed-type, depending on their contact
construction.

NOTE: The deenergized state means that no current is flowing
through the coil. The energized state means that current is
flowing through the coil.
When a normally closed relay as illustrated here is checked,
there should be continuity between terminals 1 and 2 and
between terminals 3 and 4 when the relay is deenergized.
There should be no continuity between terminals 3 and 4 when
battery voltage and ground are applied to terminals 1 and 2.
2. When current flows through the coil of a relay, its core is

magnetized to attract the iron piece, closing (ON) the
contact at the tip of the iron piece. When the coil current is
turned off, the iron piece returns to its original position by a
spring, opening the contact (OFF).

ACX00949AC

NORMALLY OPEN (NO) TYPE

DEENERGIZED STATE ENERGIZED STATE

CURRENT FLOWS

CURRENT DOES
NOT FLOW

ACX00950 AC

NORMALLY CLOSED (NC) TYPE

DEENERGIZED STATE ENERGIZED STATE

CURRENT FLOWS

CURRENT DOES
NOT FLOW

ACX00946AC

4

3

2

1

4

3

2

1

NORMALLY CLOSED (NC) TYPE

DEENERGIZED STATE

ENERGIZED STATE

CURRENT FLOWS

CURRENT DOES
NOT FLOW

ACX00947AB

COVER

SPRING

IRON
CORE

COIL

IRON
PIECE

CONTACT

HOW TO DIAGNOSE

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GENERAL <ELECTRICAL>

00E-11

3. By using a relay, a heavy current can be turned on and off by

a switch using much less current. For example, in the circuit
shown here, when the switch is turned on (closed), current
flows to the coil of the relay. Then, its contact is turned on
(closed) and the light comes on. The current flowing through
the switch is much less than that for the light.

CHECKING FUSES

M1001005000044

A blade type fuse has test taps provided to allow checking of
the fuse itself without removing it from the fuse block. The fuse
is okay if the test light comes on when its one lead is connected
to the test taps (one at a time) and the other lead is grounded.
Remember to turn the ignition switch to ON to ensure all cir-
cuits are live.

CAUTIONS IN EVENT OF BLOWN FUSE

When a fuse is blown, there are two probable causes. One is
that it is blown due to flow of current exceeding its rating. The
other is that it is blown due to repeated on/off current flowing
through it. Which of the two causes is responsible can be easily
determined by visual check as described below.
1. Fuse blown due to current exceeding rating

The illustration shows the state of a fuse blown due to this
cause. In this case, do not replace the fuse with a new one
hastily since a current heavy enough to blow the fuse has
flowed through it. First, check the circuit for shorts and check
for abnormal electric parts. After correcting shorts or
replacing parts, use only a fuse of the same capacity as a
replacement. Never use a fuse of larger capacity than the
original fuse. If a larger capacity fuse is used, electric parts
or wiring could be damaged, or could start a fire.

2. Fuse blown due to repeated turning current on and off

The illustration shows the state of a fuse blown due to
repeated current on/off. Normally, this type of problem
occurs after a fairly long period of use and is less frequent
than above. In this case, simply replace with a new fuse of
the same capacity.

ACX00948 AB

POWER SUPPLY

FUSE

LIGHT

RELAY

SWITCH
ON

OFF

ON

OFF

ACX00951AB

FUSE BLOCK

TEST TAPS

ACX00952 AB

STATE OF FUSE BLOWN DUE TO
OVERCURRENT

ACX00953 AB

STATE OF FUSE BLOWN DUE TO
THERMAL FATIGUE

HOW TO DIAGNOSE

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GENERAL <ELECTRICAL>

00E-12

CABLES AND WIRES CHECK

M1001005100041

1. Check connections for looseness, rust, and stains.
2. Check terminals and wires for corrosion by battery

electrolyte, etc.

3. Check terminals and wires for open circuit or impending

open circuit.

4. Check wire insulation and coating for damage, cracks, and

wear.

5. Check conductive parts of terminals for contact with other

metallic parts (vehicle body and other parts).

6. Check grounding parts to verify that there is complete

continuity between attaching bolt(s) and vehicle body.

7. Check for incorrect wiring.
8. Check that harnesses are secured to prevent contact with

sharp edges and corners or hot parts (exhaust manifold,
pipe, etc.).

9. Check that harnesses are secured firmly to provide enough

clearance from the fan pulley, fan belt, and other rotating or
moving parts.

10.Check that the harness between fixed parts (such as the

vehicle body) and vibrating parts (such as the engine) are
long enough to allow for vibration and movement.

BATTERY HANDLING

M1001005200048

WARNING

Battery posts, terminals and related accessories con-
tain lead and lead compounds. WASH HANDS AFTER
HANDLING.

When checking or servicing does not require power from the
vehicle battery, be sure to disconnect the cable from the battery
(

−) terminal. This will prevent problems that could be caused by

a short circuit. Disconnect the (

−) battery terminal first and

reconnect it last.

ACX00954 AB

ACX00955 AB

AC000017