FF310 Open and Short Circuit Finder and Tracer

Who it’s For:

  • Heavy-duty mechanics
  • Commercial truck maintainers
  • Marine electricians
  • Automobile restorers

What it Does:

Help you track and trace wiring to find hidden wires and circuit faults (such as corroded or worn-out cables).

How it Works:

  1. Connect the FF310T (transmitter) in series with the circuit to be traced. Use (included) fuse socket connectors if necessary.
  2. Turn on both the FF310T and the FF310R (receiver).
  3. Use the receiver to trace the wire, the audible beeps and visible flashes should indicate your proximity to the wire. It is usually best to start near the transmitter.
  4. (Optional) manually adjust receiver sensitivity if you have any issue with tracing.

Warranty & Support:

Covered by our standard 1-year warranty, and supported for much longer. Replacement parts and accessories are generally available for 10+ years.


The FF310 – FaultFinder™ is a specially designed tool for tracking and tracing short and open circuits, broken wires and current leaks on any electrical circuit with voltages from 6 to 42 Volt DC, and is used by technicians worldwide in an ample range of equipment such as automobiles, truck trailers, tractors, farming equipment, boats, forklifts, motorcycles, all-terrain and recreational vehicles, etc.

The 42V ready™ FF310’s wide working voltage range, automatic short/open detection, adjustable sensitivity levels and flexible antenna probe enables the technician to troubleshoot a complete array of common electrical problems without having to untie wire harnesses or remove body panels.

  Proposition 65 Warning

This product can expose you to chemicals including Styrene, which is known to the State of California to cause cancer, and Bisphenol A (BPA), which is known to the State of California to cause birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.


  • FF310T (transmitter)
  • FF310R (receiver)
  • CT8002 Computer safe cordless circuit tester
  • GTC062 Fuse Socket Connector Set (four sizes: ATC/ATO, Mini, Low Profile Mini, and Micro-3)
  • Hard padded case for carrying and storage
  • User’s Manual


  • Short circuit tracing
  • Open circuit tracing
  • Wire identification
  • Wire/Circuit tracing
  • Ground connections checks


  • Input Voltage range: 6 to 42 Volt DC.
  • Input DC Current: Unlimited (internally limited)
  • Voltage output: 5 Volt DC maximum
  • Current Output: 100 mA DC RMS maximum


FF310: damage precautions & warnings

The FF310 has two modes of operation:

  • 1- Open circuits: When tracing open circuits the FF310T injects into the circuit (i.e. faulty wire) a current limited, pulsing 5-volt signal, which is the same or less than most vehicles’ normal operating voltage for electronic modules and systems.
  • 2- Short circuits: When tracing short circuits, the FF310T pulses the power (current) already present in the circuit with a current limiting protection circuit.

The warning in the user’s manual regarding air bags is a precaution to avoid accidental deployment; the pulses used by the FF310 may affect the sensing circuitry and/or sensors of the airbag system.

The FF310 has been on the market for more than 12 years, and with tens of thousands of units in use, we have never received any report or complaint of the FF310 damaging any ECM, automotive module, system, or circuit.

One thing to keep in mind is that the FF310 is designed to be used in circuits up to a maximum of 42 VDC. Consequently, it is internally protected by a surge arrestor which, for safety reasons, will cause an internal fuse to blow if connected to any voltage above the 42 VDC.


Brochure: FF310-BREN
Manual: FF310-MNEN

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