A brilliant tool for the auto electrician and mechanic. Carry out the following tests on systems from 6V up to 24V quickly and efficiently: Polarity test. Power up components prior to fitting including:Cooling fan motors, Fuel pumps, Window/Sunroof motors, Relays and Lamps, Wiper motors, Tests continuity in: Switches, Diodes and Fuses, Relays, Wiring harnesses, Detect short circuits. Fitted with a sensitive short circuit protection device. Safe to use around vehicle’s electronic management systems. Fitted with 4.0m cable allowing access to the rear of the vehicle and supplied with instructions.