One wire comes in from the power source, and one wire goes out to the light(s). A 3-way switch adds two terminals for travelers, which connect two 3-way switches together.

Eric shows how to wire a three-way light switch and tune-up those gutters for spring.

If you do have this wire, Donnelly says to attach it to the green screw, which will be on your light switch. Step 5: Replace the switch plate Use a screwdriver to place the switch plate back on ...

One wire comes in from the power source, and one wire goes out to the light(s). A 3-way switch adds two terminals for travelers, which connect two 3-way switches together.