I thought my over head light switch only controlled my overhead light. It is a dimmer switch that no longer dims so I want to replace it with a dimmer that will function.

When I removed the wall plate and examined the switch I saw that it had 1 ground wire 1 red wire and 2 black wires. There are 2 capped off white wires in the box. One of the black wires is hot (I confirmed the hot wire with a voltage meter) and this hot wire was pushed into the back of the switch. The red wire and the other black wire each were screwed on brass screws located on the same side of the the toggle dimmer switch.

The replacement dimmer switch I purchased is a Lutron Ariadni dimmer which should be compatible with incandescent, LED and Halogen lights. I attached the dimmer by screwing the black hot wire beneath the black screw, and the ground wire beneath the green screw, I connected the remaining red and black wires to the 2 copper screws on the side of the new switch. When finished I discovered that this switch evidently operates more than just the overhead light because after I installed it 2 other light fixtures (both hang from the ceiling and have their own wall switches) stopped working correctly.
If I turn on the overhead light I was replacing the switch for, that light works just fine and dims when I dim it, but the other 2 lights can no longer be turned on.
If I turn off the overhead light I replaced the switch on the other 2 lights work just fine. One of these other light fixtures also has a dimmer switch which works fine.

I have no idea what the next step needs to be to get this to work properly. Help would be greatly appreciated.

  • Most of this is going to depend on the model # of the switch that you didn't provide here. Jul 30, 2023 at 22:08
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    The switch I removed was a Lutron. This switch does not have a model number printed on it, however there are patent number for this switch engraved on it- the 1st of these is US5262678A The switch I purchased to replace this is Lutron Ariadni (AYCL-153P -BL)
    – Aynne
    Jul 30, 2023 at 22:41
  • Are the 2 black wires connected to each other i.e. are they being spliced? Is there a second switch in another location which also controls this light? Jul 30, 2023 at 23:43
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    I figured it out- both black wires go together and the red takes the copper screw- I called Lutron- their customer service residential help line is fabulous
    – Aynne
    Jul 31, 2023 at 0:35

1 Answer 1


Lutron Ariadni LED+ Dimmer AYCL-153P-BL is a 3-way switch, so it does need to be treated differently from the old 2-way toggle.

The single black screw that you found on the new switch is correct for the hot wire. However, I can't tell from Lutron's instructions if that one screw is designed to hold more than one wire. To be on the safe side, get a wire nut and about 6" of black wire and splice those three black wires to make a pigtail connection to the black screw.

Lutron Diagram

The red wire seems to provide the switched power to the light in your scenario. Connect that to the brass screw, the lone screw on the one side opposite the black screw. This is important because the other brass screw would cause the switch to operate upside down.

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