Handle Heating Systems; Troubleshooting - Stihl MS 441 Manual

15.3

Handle heating systems

15.3.1 Troubleshooting

The entire handle heating system is
maintenance-free and not subject to
electrical wear. Faults in the
generator, heating elements and
wiring are generally caused by
mechanical damage.
Failures in the heating system may
be due to two reasons:
1. A break in the circuit due to
a faulty wire or component.
2. A short circuit resulting from
damage to the insulation.
1
– Remove handle moulding,
b 12.2.
: Detach plug connection from
guide and slide insulating tube (1)
towards wiring harness.
: Disconnect plug connection.
MS 441, MS 441 C
: Set heating switch (1) to
position "#".
– Set ohmmeter to "Ω" position.
– Set slide control to position "$".
: Clip test leads onto the lead from
the wiring harness and the lead
from the heating element.
Machines with carburetor heating
: Disconnect lead from heating
element (arrow).
All electrical components of the
handle heating system are
connected in series with the
ohmmeter.
If the system is OK, the ohmmeter
will show a reading of about 10 ohm
1
in the measuring range "Ω".
If the pointer does not move, there
is a break in the circuit.
If the ohmmeter shows a very low
value, there is a short circuit in one
of the components.
In both cases, each component
must be checked individually,
ensuring that the generator
connection remains separate from
the heating element connection.
– Test according to the
troubleshooting chart, handle
heating and generator,
b 15.7.1.
– Measure resistance in front
handle, b 15.6.
– Measure resistance in rear
handle, b 15.5.
– After testing, reconnect the leads
and slide the protective tube back
over the plug connection.
– Install handle moulding, b 12.2.
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