FF310 FaultFinder™

Open and Short Circuit Finder and Tracer

Tracing circuits is time consuming and thankless work. The FF310 FaultFinder helps you track down that open, short, or unidentified wire quickly and easily. With the FF310, you can get those circuits fixed, and the job done!

We’ve been making electronic troubleshooting tools for over 30 years, and this is our best one. The FF310 can track wires through interior panels, and anything else other than solid sheet metal, so you can find your problem quickly. Disassembling interior panels or bodywork and taking apart harnesses to manually inspect wires will always take more time and patience than you’ve got. The FF310 will get you to the fault straight away, so you know you’re not wasting time.

USD $249.50

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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.

The FF310 Faultfinder is capable of:

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



  • Input Voltage: 6 to 42 volts DC.
  • Input DC Current: unlimited (internally limited)
  • Voltage Output: 5 volts DC maximum
  • Current Output: 100 mA DC RMS maximum
  • FF310T (Transmitter) Internal Battery: 1604A (9V), included with kit
  • FF310R (Receiver) Internal Battery: 1604A (9V), included with kit


How-To Videos

FF310 Short Finder



FF310: damage precautions & warnings

    The FF310 has two modes of operation:

  1. Open Circuit: 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 16 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.



  Download Brochure (English)
  Download Manual (English)
  Download Manual (English/French)
  Download Manual (Portugese)
  Download Manual (Spanish)

Kit Manifest


Parts & Accessories



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.