DAF CF65, CF75, CF85 Series . Manual — part 491
5
CF65/75/85 Series ≥0E621376
Fault finding
DIAGNOSTICS
1-3
1.2 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 lights up, 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.
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W 5 03 016
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DIAGNOSTICS
Fault finding
CF65/75/85 Series ≥0E621376
1-4
1.3 EARTHING PROBLEMS
Earthing problems are mainly caused by
corrosion between the contact surfaces of
electrical connections.
A poor earth connection of the main earth
circuit (2) between cab and chassis may result in
a current through the steering shaft (1).
E502316
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2
To check this main earth connection, two
complementary tests must be carried out.
-
A current measurement using a current
probe.
-
A voltage loss measurement using a
multimeter.
A current probe, which is a special tool (DAF no.
1453183), must be used for a current
measurement; this measures the current
through the steering shaft (1).
The current measurements have to
be carried out while the cab is in the
driving position.
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200520
5
CF65/75/85 Series ≥0E621376
Fault finding
DIAGNOSTICS
1-5
INSPECTION 1, MEASURING THE SYSTEM
CURRENT
1. Open the grille.
2. Switch on vehicle ignition and as many
consumers as possible, e.g.:
-
dipped beam
-
heater fan in position 4
-
spotlights, etc.
3. Use the current probe to check whether the
power consumption through the battery
cable at the battery is between 20 A and 40
A. Switch on extra consumers if this is not
the case until the power consumption is
between 20 A and 40 A.
4. Then measure the system current through
the steering shaft (1) using the probe. Make
sure that the current probe is placed in the
right position (direction of current) and its
jaws are closed around the steering shaft.
5. Depending on the measured current value,
the following actions need to be carried out:
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E502267
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200520
5
DIAGNOSTICS
Fault finding
CF65/75/85 Series ≥0E621376
1-6
Measured
current value
Measures to be taken
< 2.0 A
-
The main earth connections are in good order, end of inspection 1. Continue
with inspection 2.
≥ 2.0 A and
< 5.0 A
-
Inspect - and if necessary repair - all main earth connections from the cab to
the negative battery terminal between the following points:
-
battery earth and cab earth
-
cab earth and flywheel housing earth
-
flywheel housing earth and chassis earth
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th
d b tt
th
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g
-
chassis earth and battery earth
Note:
A voltage loss measurement must be carried out to identify which earthing point
is in poor condition. This measurement is described later on in this procedure.
-
The current value through the steering shaft must be less than 2.0 A after
-
The current value through the steering shaft must be less than 2.0 A after
repair. Otherwise one or more earth connections are not yet in good order and
the main earth connections must be inspected again and if necessary
repaired.
-
If the current value is < 2.0 A, the main earth connections are in good order:
end of inspection 1. Continue with inspection 2.
≥ 5.0 A
-
Inspect - and if necessary repair - all main earth connections from the cab to
the negative battery terminal between the following points:
-
battery earth and cab earth
-
cab earth and flywheel housing earth
-
flywheel housing earth and chassis earth
-
chassis earth and battery earth
Note:
A voltage loss measurement must be carried out to identify which earthing point
is in poor condition. This measurement is described later on in this procedure.
-
The current value through the steering shaft must be less than 2.0 A after
repair. Otherwise one or more main earth connections are not yet in good
order and the earth connections must be inspected again and if necessary
order and the earth connections must be inspected again and if necessary
repaired.
-
If the current value is < 2.0 A, the earth connections are in good order.
Note:
A high current through the steering shaft can affect the mechanical condition of
the steering shaft bearing.
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200520
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