General Technologies FF310 Fault Finder for Electrical Wiring Open / Short Circuit - Manual (Page 6)

Page 9 Page 8
12.3 Some circuit characteristics that may affect the tracing of a wire:
•
Electromagnetic loop size and geometry, etc. may affect the range of the FF310
Receiver. For example for circuits in which the live and ground (return) wire
run parallel and close to each other in the same circuit, the two magnetic fields
interaction may weaken the signal, thereby reducing the FF310 range.
•
Wires enclosed or tightly lining the metal frame or body of the vehicle, (i.e.: door
frames), have the same effects as having the live and ground wires running in
parallel in the same circuit since, the metal frame or vehicle body will be acting
as a ground wire. Another unfavorable factor may be due to the channeling effect
steel parts have on magnetic fields. These two cases, individually or combined,
will reduce and sometimes impede the tracing of the wire sections affected.
Hint: Whenever possible the short circuit mode of operation should be used, be-
cause it provides with the best tracing capabilities.
13 - Special Tracing procedures
• In all cases, first set the FF310R at the lower sensitivity level and increase it as
necessary. Proceed as indicated in the sections of this User’s Manual applicable
to your situation.
•
Always after locating a probable fault area, verify several points in the wires on both
sides (before and after) the suspected area. The signal should be present at only
one side of the fault (open or short). This procedure will help avoid confusing a signal
loss with the actual trouble point.
Fig. 8 - Tracing Wires inside bundles and conduits
Fig. 9 - Simplified dome light circuit hook up for wire tracing
•
When tracing or identifying wires connected to lightly loaded circuit (low
currents), this reduces the range of pick up significantly. A possible solution is after
connecting the FF310T - transmitter in series with the circuit to trace, is to replace
the load (light bulb, module, etc.) with a direct connection to ground. This allows
the FF310T to inject a more powerful signal easier to detect.
•
For the cases in which it is suspected the layout of the wires is the cause of a very
difficult to pick up or weak signal, a dramatic increase of the range can be
accomplished by “spreading” the circuit.
•
This is achieved by means of connecting a jumper wire between the live wire
(preferably at a termination point in the circuit such as a light bulb socket or a switch,
etc.), and a ground point somewhere else in the vehicle ( see Fig. 9). This last method
should be used only as “last resource” and with the FF310R set to low sensitivity,
as it may make the pinpoint of the precise location more difficult due to the much
increased range.
•
Always verify that the FF310T is connected in series with the circuit being tested and
that its red indicator light is on, as this confirms a proper connection and will limit the
amount of current flowing in the circuit.
Fig. 7 - Detection field when tracing short-circuits with the FF310
13.1 Wire bundles and conduits:
• Special care should be given in the case of tracing a wire inside a bundle or
conduit when there is a split. In this case it may be possible to follow the wrong branch
for a short distance and still receive a positive audio/visual indication.
•
To avoid following the wrong path, which could happen if the probe picks up the
signal from the other nearby branch of the circuit, the branches should be swept
maintaining the probe outside the apex area between the split, as shown in Fig. 8.
•
Careful attention should be paid to the beeping and flashing speed of the tracer unit
indicators, as these provide the necessary feedback to evaluate the proximity of the
probe to the wire being traced.
13.2 How to increase the pick up range when tracing wires