A continuity tester for a lamp, coaxial, plug connector has a receptacle connector with first and second coaxial, annular receptacle contacts at a same axial spacing apart as power and ground contacts of the lamp connector for electrical engagement when plugged therein and, a probe contact engageable with only the power contact. First and second LEDs connect to a battery via first and second parallel circuits. A biasing resistor in the second circuit ensures that battery power is provided to only the first LED when a battery circuit is completed only by electrical engagement of the first contact and the probe contact with the power contact of the male coaxial connector to signal absence of a short circuit and to only the second LED when a circuit is completed also by engagement of the second tester contact with the ground contact of the lamp connector to signal a short circuit.