Diagnostic tool for trailer lights

A trailer light tester for testing a trailer comprising a plurality of trailer lights, a plurality of trailer light circuits and a trailer connector, said tester comprising:

• a hand-held enclosure;
• a battery within said enclosure;
• a circuit board within said enclosure and electrically connected to said battery, said circuit board comprising electronics and a plurality of lamps, each lamp of said plurality of lamps for signaling the operational status of an electrically associated trailer light circuit of said plurality of trailer light circuits;
• a multi-pin connector on said enclosure, said multi-pin connector for electrical connection between said trailer connector and said circuit board, said multi-pin connector comprising a plurality of connector pins, each connector pin of said plurality of connector pins being connected to an electrically associated lamp of said plurality of lamps, wherein said plurality of lamps are electrically connected to said battery in parallel, such that each lamp automatically signals said operational status of only a respectively electrically associated trailer light circuit connected to a respectively electrically associated connector pin;
• a removable adapter for mating to said multi-pin connector, said adapter comprising a plurality of adapter connector pins, each adapter connector pin being connected to an electrically associated connector pin of said plurality of connector pins and an adapter collar attachable to said multi-pin connector;
• and,
• a plurality of indicia, each indicia of said plurality of indicia being associated with each lamp of said plurality of lamps and describing said trailer light circuit electrically associated with a respectively electrically associated lamp of said plurality of lamps;
• wherein said adapter is for electrically connecting said multi-pin connector to said trailer connector.