[JRTJH]

In RV's until about 2018 (or around then) typically the electrical connections were the same as a stick and brick (S&B) house. White wires were negative/neutral and the black wires were positive/hot. In around 2018, Keystone changed the color code for wires to match those in automobiles rather than S&B houses.

I'd guess that if your wiring is the factory wiring, then those white wires should be ground. Whether they are for an electric tongue jack, a set of electric stabilizers, a light, your trailer brakes (through the break away switch wiring) or some other device is a question I can't answer.

You'll need to do some "scouting around" your trailer tongue to see what's not connected, what's possibly missing and where those wires go. At any rate, if they're OEM, white is ground. If they are part of something installed by a previous owner, then who knows what color wires he used ??????