This tester is for a trailer/caravan and tow bar socket/plug checker. 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
4 In 1 Optical Power Meter -70 to 6dBm Red Light Laser Network Cable Test Lighting Optical Fiber Tester Optic Tester Tools
Aliexpress UK
Just plug the tester in the 7pin /13 pin socket or the 7 pin /13 pin plug of the trailer or caravan and press the yellow button on the side of the tester. 1 x Plug Socket Diagnostic Tool (As seen in photos).
eBay
Rechargeable Visual Fault Locator FTTH 15MW/30MW/50MW Fiber Optic Tester SC/FC/ST 2.5mm interface Optical Fiber Tester Tool
Aliexpress UK
This12V 7 Pin Trailer Lights Plug & Socket Wiring Circuit Tester is designed for testing the lighting circuits on both towing vehicles and trailers/caravans etc. 12V electrical trailer plug & socket wiring tester.
eBay
1/10/20/30/50mW Visual Fault Locator Fiber Optic Cable Tester Pen 2.5mm Interface(SC/FC/ST) FTTH Optical Fiber Tester Tool VFL
Aliexpress UK
Proven Reliability: With a rich history of excellence, Sealey tools are trusted by professionals worldwide. Also tests the 12V continuous/ignition live feeds and the reversing lights - not part of the current MOT test, but useful when diagnosing electrical faults.
eBay
COMPTYCO Visual Fault Locator 1/10/20/30/50mW Fiber Optic Cable Tester SC/FC/ST 2.5mm Interface FTTH Optical Fiber Tester 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
SC8108 Portable LCD Network Tester Meter&LAN Phone Cable Tester Meter with LCD Display CAT5 RJ45
Aliexpress UK
This product is used to test the electrical trailer sockets that are fitted to the vehicle. If the sockets are faulty, secondary lights fitted to the trailer may not work. For S and N systems to test the trucks towing sockets ISO 3731 & ISO 1185.
eBay
OPTFOCUS Network Cable Tester CAT5 CAT6 POE Checker Network Line Finder OPM VFL 10mw High Quality Tester
Aliexpress UK
This 12V 7 PIN 13 PIN CAR TRAILER TOWING LIGHTS WIRING CIRCUIT PLUG SOCKET TESTER SET by adapter-universe is essential for testing trailer towing lights. The tester includes functions for turn signals, brake lights, and rear fog lights, all of which are crucial for ensuring safety while towing. The package comes with a 1x trailer tester and a 9V battery is required for operation. The black tester is compatible with universal 7Pin to 13pin connectors, making it a versatile tool for any trailer.
eBay
TOOLTOP Network Cable Tester Optical Power Meter Multimeter VFL 4 in1 LAN Line Finder PoE Tester for Structure Cabling
Aliexpress UK
This12V 7 Pin Trailer Lights Plug & Socket Wiring Circuit Tester is designed for testing the lighting circuits on both towing vehicles and trailers/caravans etc. 12V electrical trailer plug & socket wiring tester.
eBay
Cable Tracer Applicable for Tahlitech CCTV IPC Tester IPC 5100Plus IPC 5200Plus IPC1910 Plus IPC1800Plus CCTV Tester Cable Trace
Aliexpress UK