In some cases, it might be best -- and safest -- to contact an electrician. Don't show this again. Attach the red and black wires from the other bundle four-wire to the switch's brass terminals. Don't put up with old three-way light switches like this. Diagram 1: Here's the list:. Wiring a Light Switch.
If not, link them together with a wire nut.
3 Way Switch Wiring Diagram
Before you do anything, switch off the breaker on your main electrical panel. Three ways are always confusing! Smart light switches, though, tend to need a neutral wire hookup. Box 1.