This adapter is a lighting and cable tester for trailers and towing vehicles. To do this, you simply have to insert the tester into the socket or plug to be tested, press the test button and a clear diagnosis is made via the LED display.
eBay
Network Ethernet Cable Tester UTP STP Shielded Cable And Telephone Line Connectivity Check Tool
Aliexpress UK
Just plug the tester in the 7 pin socket or the 7 pin plug of the trailer or caravan and press the yellow button on the side of the tester. This 7 Pin Tester is designed to indicate a failure in the wiring on both towing vehicles and trailers/caravans etc.
eBay
Multifunctional Network Cable Tester HDMI Compatible RJ45 8P8C LAN POE Anti-Burn RJ11 Telephone Line Test Tool
Aliexpress UK
This tester has one side to connect the 7-pins plug of a trailer and another side to connect the 7-pins socket of a car. This tester indicates quickly if a failure concerns the wiring of the car or the wiring of the trailer.
eBay
OPTFOCUS Optic Fault Finder 20KM FTTH FTTA FTTB Handheld Fiber Optic Fault Tester VFL 10mw Fiber Optic Test Tool
Aliexpress UK
The body plugs directly into either 7-pin N-type plugs or sockets and gives a continuity test on all lighting circuits. 12V electrical trailer plug & socket wiring tester. 1 x 12 Volt 7 Pin Trailer Plug and Socket Tester.
eBay
Cable Tracker RJ11 Wire Tracer Ethernet Tracker Telephone Tone Generator Line Toner Tester For Network Telephone Line
Aliexpress UK
Just plug the tester in the 7 pin socket or the 7 pin plug of the trailer or caravan and press the yellow button on the side of the tester. This 7 Pin Tester is designed to indicate a failure in the wiring on both towing vehicles and trailers/caravans etc.
eBay
OFW Optic Fault Finder Mini OTDR Visual Fault Locator 20KM Optical Fiber Breakpoint Tester 10MW Red Light Support English
Aliexpress UK
Just plug the tester in the 7 pin socket or the 7 pin plug of the trailer or caravan and press the yellow button on the side of the tester. This 7 Pin Tester is designed to indicate a failure in the wiring on both towing vehicles and trailers/caravans etc.
eBay
JILONG OTDR 1310/1550/1577/1625/1650nm 31dB/29dB VFL Optical Time Domain Reflectometer OPM Active Fiber Live Tester
Aliexpress UK
7Pin 13Pin Car Towing Trailer Cable Circuit Plug Socket Tester Detector Auto【UK】. - Trailer tester for 7 pins plug and socket connection. Put the plug in the connection of the tester. Press the yellow button on the side of the tester.
eBay
TEKCN TC-200 Optical Power Meter/OPM/ VFL/Red Light Pen/Visual Fault Locator/Fiber Optic Tester for FTTX & Telecom Maintenance
Aliexpress UK
Waterproof tap cover Frost Protector outdoor Insulation Garden Winter Jacket. 2PC Car Electromagnetic Interference Antifreeze Portable Snow Remover. Just plug the tester in the 7 pin socket or the 7 pin plug of the trailer or caravan and press the yellow button on the side of the tester.
eBay
FTTH Fiber Optic Cable Tester Tool Kit (Optional) Optical Power Meter(OPM -70 ~+10dBm)&Visual Fault Locator(30/1/10/20/50mw VFL)
Aliexpress UK