Trying to replace light switch

Question

I am replacing a toggle light switch. The switch has one ground screw and two terminal screws.

I can’t figure out which wires go to which screws.

Coming out of the box are three white wires connected together, two black wires connected together, one red wire, and one black wire.

enter image description here

GUESSING because no real information provided, but sounds like you have a 3-way switch. Do you have the old switch or any other information? — Jason, Apr 12 '21 at 19:12
People need to take picture of the existing thing before ripping it out. Once you rip out the old switch, you then need to test if the wires are actually what the color says they are, because lazy people skip that step, and you can die from it if you get it wrong. — Nelson, Apr 13 '21 at 02:14

score 0 · Answer 1 · answered Mar 13 '21 at 18:31

0

You only need to connect the red and the black to the terminals with brass-colored screws. It doesn't matter which terminal gets which wire. There's no ground wire in the box, so you have nothing to attach to the green ground terminal. You should put a wire nut on the connection of two black wires.

answered Mar 13 '21 at 18:31

1

I did that. This is a bedroom light switch. After I did what you suggest, not only does the ceiling light not turn on but the closet light also no longer turns on. Also, everything that was connected in the room no longer turns on even if I bring it into another room. If I bring something in that wasn’t connected in the room, that something does turn on in the room. There’s power coming in but no lif – Tracy Mar 13 '21 at 20:43
1

There’s power coming in but no lights. Everything connected in the room blew out. No longer works. – Tracy Mar 13 '21 at 20:48
Didn't your original question say you're replacing a dimmer switch that was connected to only the red and (single) black wires? – Mar 14 '21 at 13:09
Yes. Their were two black wires connected to the dimmer. One was connected to the red wire from the box and the other was connected to the black wire from the box. – Tracy Mar 14 '21 at 14:34
I connected the red a black wires to the terminal screws and not only doesn’t the ceiling light work but now the closet light doesn’t work. The room is a bedroom. All outlets work but the ceiling and closet lights don’t work. – Tracy Mar 14 '21 at 14:36
The circuit is connected to two other bedrooms and everything works in those two other bedrooms. Here’s – Tracy Mar 14 '21 at 14:37
Your house has aluminum wiring. That's why there were short copper wires between the red and black wires and the dimmer switch. The switch you're trying to install has "solid copper wire only" stamped on it, so, if you stick with it you'll need to do something similar. There are switches that will take aluminum wires, though, and you'd best get one of them. This web site under the tag "aluminum-wiring" has lots of discussion. The wire type is a long-term safety issue unrelated to today's problem - just additional aggravation. – Mar 14 '21 at 20:20
In your last response to earlier comments you said that other things on the same circuit still work. By "same circuit" do you mean on the same circuit breaker? Also do you now think that it's just the closet light and the ceiling light that don't work? You earlier thought there was a lot more wrong. The first comment/question from @ThreePhaseEel asked if you have some way to test for voltage. You'll need something, unless you see some obvious problem in the box, like one of the wires coming loose from the switch. – Mar 14 '21 at 20:33
@stretch at this point, there is significant safety issue with mixing copper and aluminum improperly. Please see How to connect aluminum with copper wires. This just got significantly more complex and an electrician is probably in order. – Nelson Apr 13 '21 at 02:21
@Nelson: agreed: it is time to call an electrician. – Apr 19 '21 at 13:23

Trying to replace light switch

1 Answers1