FaultFinder: Open and short circuit finder and tracer

Discontinued - see FF310 for new improved model

  The FF300 is easy and flexible to use. It only requires connecting the transmitter in series with the circuit or wire under test, (i.e.: in place of a blown fuse, across a connector, in series with an open wire, a light bulb socket, etc.), and scanning the circuit/wire with the tracer's flexible probe to find the trouble spot.

  This professional tool will work on all kinds of circuits with voltages between 6 and 36 Volt DC, such as those found in automobiles, trucks, trailers, tractors, boats, RVs, etc… With its wide working voltage range, automatic open/short detection, flexible probe and adjustable sensitivity, the FF300 Faultfinder enables you, to troubleshoot a complete array of common problems, in a wide variety of vehicles.

  Now with the FF300 you can locate short circuits, broken wires, current leaks and perform wire tracing quickly and easily spending only a fraction of the time and effort required when using conventional methods. In most cases, you will even be able to locate the problem area without having to untie harnesses, open conduits or remove panels.


  • No Ground or clip required
  • Operates on DC voltages from 6 to 36 volts
  • Internally protected against power surges and overloads
  • 9" flexible probe allows reaching wires in congested places
  • Transmitter and Receiver LEDs show open or short circuit conditions
  • Variable audio/visual signal provides fast and intuitive feedback on the circuit/wire proximity
  • Adjustable sensitivity for all tracing situations
  • No wire piercing required, non-contact technology!
  • Tracing of wires is made possible even inside bundles, conduits, behind panels, under carpets, upholstery, etc.
  • Transmitter has auto polarity and leads with 5 amps alligator clips

Technical Specifications

FF300T (Transmitter)

  • Indicators: Green LED for power On and Open circuits. Red LED for short circuits
  • Power source: 9-volt alkaline battery. Duracell type MN1604 (included)
  • Battery life: approx. 50 hrs
  • Connector: Two 5 A alligator clamps with auto polarity and 18" long cable
  • Physical dimensions: 4.375" (H) x 2.56" (W) x 0.937" (D) - (111 x 65 x 23 mm) - Excluding cable and probes
  • Weight: Approximately 5.6 Oz ( 156 g) Including battery

FF300R (Receiver)

  • Sensitivity: Three user selectable sensitivity levels (low, medium and high)
  • Receiver probe: Flexible 9" gooseneck insulated steel probe
  • Indicators: Green LED indicator for power on and open circuits. Red LED indicator for short circuits
  • Variable flashing and modulated audible signal
  • Power source: Standard 9-volt alkaline battery. Duracell type MN1604 (included)
  • Battery Life: approx. 50 hrs. Auto Power Off
  • Physical dimensions: 4.375" (H) x 2.56" (W) x 0.937" (D) - (111 x 65 x 23 mm) - Excluding antenna and probe
  • Weight:Approximately 5.2 Oz ( 145 g) Including battery

Electrical Specifications

  • Input Voltage range: 6 to 36 Volt DC
  • Input DC Current: Unlimited (internally limited)
  • Voltage output: 5 Volt DC maximum
  • Current Output: 200 mA DCrms maximum


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

For use in

  • Automobiles
  • Trucks
  • Trailers
  • Boats
  • RVs
  • Any 6 to 36 Volt DC powered circuits


  • FF300T ( transmitter)
  • FF300R (receiver)
  • Hard padded case for carrying and storage
  • User's Manual