3 way dimmer switch help


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Hi Dominick,

I have an old rotary dimmer switch that I want to replace with a newer and similar switch. My father had tried to do it some years ago but he wasn’t used to 3 way applications. I tell you this because in his attempt he did something strange to the circuit when he put the old dimmer switch right back where it was: the other non-dimmer switch, which he did not work on, has since only been functional when the dimmer switch has been left in the pushed-on position. The non-dimmer used to work fine on its own before this. I have included some pictures of the current dimmer connections, and ask you to consider that something is not right with these connections. Also, I am wondering how to connect my new dimmer. It has a green wire, 2 black wires, and a red wire. I don’t know where to attach them.


Thank you!


Answer ( 1 )


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    The wiring looks correct for the dimmer switch in the pictures. The dimmer switch may have short in it.

    If you install a new one…


    The black wire on the right side in the wall in your picture looks like your hot wire from the breaker box. The other black wire is a traveler and the red wire in the wall is also a traveler to the other switch which is connected to the lights.

    Remember to turn off power first and remember to turn it back on once done wiring.

    If you wire it and nothing happens swap the black wires.

    On your new dimmer switch connect the hot black to the COM the other black to the black traveler and red to the red traveler in the wall. The green wire will connect to the bare copper wire in the wall or screw into the box.