DAF LF45, LF55 Series. Manual — part 337
5
LF45/55 series
Fault finding
DIAGNOSTICS
3-3
3.2 OPEN CIRCUIT
Suppose a consumer is not functioning. The
fault may be in the consumer itself, or there may
be an open circuit in the wiring.
First switch on the consumer. Then check the
consumer for voltage using a test lamp. If no
voltage is found, first check whether the fuse is
still intact.
If there is voltage at the fuse, check the wiring
from the fuse to the consumer. This means
every wiring connection must be checked.
Stop at the first wiring connection that has no
voltage. The open circuit will be between this
connection and the previous one.
However, if there was a voltage at the consumer,
there may still be an open circuit in the negative
(earth) wiring. Check this using a test lamp.
Ensure that the relevant circuit is switched on.
Connect one end of the test lamp to earth and
the other end to the earth connection of the
component to be checked.
If the test lamp comes on, the earth connection
of the component is interrupted. If the test lamp
does not light up, the earth connection will in
many cases be in good condition.
If both the positive and negative connections
are in good order, the consumer in question
must be replaced.
W 5 03 015
W 5 03 016
1
200440
5
DIAGNOSTICS
Fault finding
LF45/55 series
3-4
3.3 EARTHING PROBLEMS
Earthing problems are mainly caused by
corrosion between the contact surfaces of
electrical connections.
Earthing problems can only be detected using a
multimeter (preferably digital). A digital tester is
preferable because usually only a few volts will
be measured and an analogue meter is
generally not precise enough for this purpose.
To find out whether a specific earthing point has
a good earth connection, use a voltmeter to
measure the voltage between the negative
battery pole and this earthing point.
Switch on as many consumers as possible.
If there is a correct earth connection, no voltage
should be found.
In practice, however, a loss of approx. 0.5 volts
will often be measured.
If the reading is higher, the earth connection
must be checked carefully.
In this way, the earth connections of all
consumers can be checked and measured.
W 5 03 014
1
200440
5
LF45/55 series
Contents
COMPONENTS
1
CONTENTS
Page
Date
1. GENERAL
1-1
200440
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . .
1.1
Multimeter
1-1
200440
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . .
1.2
Scopemeter
1-2
200440
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . .
1.3
Signal measurements
1-2
200440
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . .
2. DESCRIPTION OF COMPONENTS
2-1
200440
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . .
2.1
Inductive sensor
2-1
200440
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . .
2.2
Vehicle speed sensor
2-2
200440
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . .
2.3
Temperature sensors
2-3
200440
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . .
2.4
Pressure sensors
2-4
200440
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . .
2.5
Alternator
2-4
200440
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . .
2.6
Windscreen heating relay
2-6
200440
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . .
3. DIAGNOSTICS
3-1
200440
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . .
3.1
Diagnostics in electrical systems
3-1
200440
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . .
2
200440
5
COMPONENTS
Contents
LF45/55 series
2
2
200440
Нет комментариевНе стесняйтесь поделиться с нами вашим ценным мнением.
Текст