Rewiring a landscape trailer

I wire mine from the tongue straight to the taillights and then take a white wire and brown wire back to the markers. White is ground and brown is marker/tail lights. I do not ever use wire nuts or crimp on connections. I solder all connections and shrink wrap (remember to put the shrink tubes on before soldering) l very rarely have any problems with my wiring unless the squirrels decide to eat the wires. Why the heck to squirrels eat wires????
As Cavie said-the color code is Yellow--left turn signal/Green--right turn signal/Brown--markers, tail lights/white--ground.