This might seem intimidating but it does not have to be. With these diagrams below it will take the guess work out of wiring.

Help Deciphering Odd Wiring From Old Dimmer Doityourself
Old 3 way switch wiring. In box 1 disconnect a wire on the old switch and attach it to the correct terminal on the new one. The alternate 3 way switch wiring configuration california or west coast was used as a way to wire 3 way switches and be able to supply line voltage to either switchthis configuration is no longer allowed as the neutral is not present in each switch box. Connect the two remaining traveler wires to the two brass or light colored screws. Isbn 0 07 057879 6 if you still dont own this tome and youre working the residential repairs beat then go to the back of the class. Take a closer look at a 3 way switch wiring diagram. With a pair of 3 way switches either can make or break the connection that completes the circuit to the light.
3 way switch wiring diagram. Conventional 3 way wiring is not very complexwith conventional wiring the line line voltage connects to the common of one switch. Two very old three way switches are depicted in the photo above. Connect the ground wire to the green screw. Remove the cover plate from the switch box with a slotted screwdriver. Shapiro covers a lot more than carter 3 ways.
Wrongun et has beaten the carter 3 way to death. Methodically dealing with one wire at a time will help avoid confusion and mistakes. When wiring a 3 way switch first screw the terminal screws of the new switch until they are difficult to turn. Unscrew the three way switch you suspect isnt operating properly from the box. Before disconnecting the switch wires label each wire for easy reattachment later and mark the hot white wire with a black marker. Wiring a 3 way light switch.
3 way switch schematic wiring diagram. Wiring a 3 way light switch is certainly more complicated than that of the more common single pole switch but you can figure it out if you follow our 3 way switch wiring diagram. This is only a wiring schematic and not the actual wiring method used for 3 way switch installations. Shapiros old electrical wiring page 57 for the wiring diagram. Two very old three way switches. 2 go to david e.
Connect the wire marked common to the black or dark colored screw. Below is a simple 3 way schematic that can be applied to all three way electrical light switch connections. Pick the diagram that is most like the scenario you are in and see if you can wire your switch.