4 Way Switch Wiring Diagram - Easy Do It Yourself Home A 4 way switch wiring diagram is the clearest and easiest way to wire that pesky 4 way switch. I have a few of the most common ways in wiring a 4 way switch to help you with your basic home wiring projects. Do you need a 3 way switch wiring diagram ? OPTION #1: Power from light fixture to light switch3 Way Switch Wiring Diagram · 4 Way Switch Wiring Wiring a 4-way Switch - how-to-wire-it Wiring a 4-way switch is simply adding a switch to an already existing 3-way switch circuit. This allows you to control a load from other locations in addition to the (2) locations that a 3-way circuit provides. First of all we need to go over a little basic terminology on switches.