Standard Color Code for Wiring Simple 4 Wire Trailer Remember that Yellow has a L in it so that is the left side brake/turn signal and green has a R in it so that is the right side brake/turn signal. The colors for wiring a 7-way connector are as follows with the 4 colors of the 4-way connector remaining the same. White-Ground. Brown-Tail/Running Lights.4.8/5(91)Brand: DekaWiring FAQ · 16-4B-1 220 Volt, 4 Prong Plug Wiring by Jaden - Alpha Rubicon Some 220 volts AC plugs have 4 prongs. This simply means there are two hot wires, one neutral and one ground. The black and red will each carry 110 volts. The load (tool, appliance or whatever) uses 110 volts from each wire and therefore is 220 volts. Notice on the prongs that the bottom one has a 90-degree bend inward. That’s the ground.