Gunson, manufacturers of simple, effective diagnostic tools have launched a polarity circuit tester, safe for using around engine management systems.

Retailing at around £9.99, it has many uses. Instantly locating short circuits without wasting fuses, tracing bad ground / earth contacts, and testing a range of devices without connecting jumper wires, such as cooling fans, window regulator motors, electrical fuel pumps, relays and lamps.

The Gunson Polarity Tester (Part 77001) is suitable for 6, 12, 24 volts.