Test lamp

An automotive tool used to test powered circuits on 6-24 volt systems such as headlights, horns, signal, or tail lights. It consists of a handle with a bulb and sharp probe and a lead with a crocodile clip, The sharp probe is used to pierce the insulation on the wire leading to the defective part; if the bulb glows, the circuit is complete. Simpler designs do not feature a probe, but come in a standard screwdriver shape