This is the quickest and easiest way to test the wiring of 7 pin towing plugs and sockets (DIN ISO 1724). This handy test device guarantees the quickest and easiest search for cable line defects on trailers and towing vehicles. Simply attach the tester to either a socket or plug, press the test button and a clear diagnosis will be made via the LED display which will indicate the result. If all LED are lit, then everything is correct. If any LED is not lit, then there is a connection problem with that circuit. The tester is clearly labelled to identify the cause. No external power source (running engine, car battery, etc.) is required as the tester has its own. Requires a 9V battery (not included). A portable hand held design. The following functions can be tested: Turn signals, left and right. Brake light.
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