Sealey 6 24v auto tester probe sealey pp1 a brilliant tool for the auto electrician and mechanic carry out the following tests on systems from 6volt up to 24volt quickly and efficiently polarity test power up components prior to fitting including cooling fan motors fuel pumps window sunroof motors relays and lamps and wiper motors tests continuity in switches diodes and fuses relays and wiring harnesses detect short circuits locate bad earths quickly fitted with a sensitive short