Testing Truck Trailer Plug. Used to test the trailer power supply wiring whether normal or not. If the trailer plug wiring on your vehicle or trailer is damaged or not working correctly, you can replace the connector with a CURT splice-in plug or socket.
7 Pin Trailer Plug Socket Light Tester for Car Truck ... (Howard Lucas) Just like your car or truck's brake and signal lights. If this is correct, then the faults are not with your trailer plugs. Check this category or use the search box above, you will find them all here!
If the trailer plug wiring on your vehicle or trailer is damaged or not working correctly, you can replace the connector with a CURT splice-in plug or socket.
New 12V 7 Pin Trailer Tester, Socket Plug Car Towing light ...
7 Pin Auto Car Trailer Towing Light Cable Circuit Plug ...
If the trailer lights work on your buddy's truck, then the trailer lights work - period. Something we haven't asked: Have your trailer lights EVER worked with this combination truck/trailer? Put the plug in the connection of the tester.