Expert Advice from Start to Finish revised ed. Three-way and four-way switches shall be wired so that all switching is done only in the ungrounded circuit conductor This way, you'll have a record of how everything was connected and working properly initially. You've gained the skills to tackle that as well. How 3-way and 4-way switch circuits work Controlling a light with two or more switches This page describes how to use 3-way and 4-way switches to control lights from two or more locations. Physics Miscellaneous tips and info Rick Matthews.
In the 2nd diagram below, blue wires are used for travelers.
Help wiring a 3 way switch
In this option you will have seven 7 wires in the first box. Equipment for new installations is not commonly carried by electrical suppliers, although it is still possible to find parts for maintaining existing installations. Notice that there is a 3-conductor cable coming into the first box, then a 4-conductor cable going from left box to right box, then a 3-conductor cable going from the right box to the load. The black and red wires in the other bundle four-wireentering the box from up top, are the travelers wires from the other switch. Likewise you should confirm the white neutral wires are squared away here as well. The bare copper wires tie together with a wire nut. Just to be safe, use a voltage pen to check for a live current.