4 Way Switch Wiring Diagrams - Do-it-yourself-help 4 Way Dimmer Switch Wiring Diagram. This is the wiring for a dimmer in a 4 way circuit. Three-wire cable runs between all the switches and 2-wire cable runs to the light. To make this circuit work, a 3 way dimmer can be used in place of one, or both of the standard 3 way switches. Installing Dimmers for 3 Way and 4 Way Switches Fully explained 3 way dimmer switch wiring diagram will take the mystery out of wiring a 3-way dimmer switch. 4 Way Switch Wiring Fully explained 4 way switch diagrams. 4-way switches are a convenient way to operate lighting fixtures from three or more locations.