Found at a friend's house.

This 3-way switch is working fine, but it seems to have 2 of the wires permanently bonded together under one screw terminal, with the other one remaining unused. Presumably the red wire on the other side is the traveler (but it's not clear).

According to my friend, any attempt at rewiring this using all three screw terminals results in the other switch only working when this switch is in a particular state.

How is this working? Is there anything wrong with leaving it like this? If so, how can it be fixed?

enter image description here

  • So you have 2 switches that can turn a single light on and off. If the switch in the photo turns the light on in its down position, then the second switch turns the light off, can the switch in the photo turn the light back on in its up position?
    – HandyHowie
    Mar 8 at 11:59
  • 1
    Can you post photos of the wiring at the other switch please? Mar 8 at 12:41
  • 1
    This might just be a quirky way of chaining the hot to elsewhere. Why, if it works, are you messing with it in the first place? Mar 8 at 19:01
  • Is the switch on the other end a smart switch, dimmer, etc.? Mar 8 at 23:07
  • Yes, switch on the other end is a smart switch!
    – peter
    Mar 9 at 15:58

2 Answers 2


You need to find which of the 2 wires on the black screw is the line hot from the panel. ( having both there is making them both hot all the time.)

The line that is hot stays on the black screw.

The other is moved to the gold screw above the black.

That should correct the problem, unless the other switch is wired wrong as well.

Try this solution and report back.


This is an original 3 way switch, but wired as regular switch.

The 3d wire from the 3 way is missing (not connected) so it is not performing the 3 way switch function.

3 way switch needs 3 wires to work.

It does have 3 wires on the switch but two of them are connected together under one nut.

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