Most problems are on the truck connectors or the trailer plugs, after a few connections and disconnections the little screws come loose and the wires pull out, when I instal new connectors I twist the wires and add a dab of solder, this alaws me to tighten the small screw pretty tight.
There is a product sold at Home Despot that is liquid tape, I use this to seal the connectors where the wires are attached so that no water or moisture gets there, I also use electricians tape to seal where the wire cable enters the connectos and the sockets.
If the sockets or receptacles get damaged I eplace them, wigling the plugs also widens the round female ends and that can cause an intermittent connection.
navegator