7 Round pin circuit tester designed to quickly test lighting circuits for tractor and trailer. Plug into the end of the cable nearest to the trailer, bring cable into the cab check each circuit in your lighting system. If one or more of the LEDs in your tester do not light up the circuit is faulty.

• "œOne person testing" for male and female 7-way round pin tractor trailer plugs
• Easy installation and removal with winged grip
• Allows bypass of trouble circuitry while on the road
• LEDs indicate working circuit
• Plugs into vehicle side socket
• Weatherproof
• Sold individually