The house I bought has numerous light/fan switches with smart switches. The one in my garage started going crazy so I removed it and bought a regualr dual switch to replace it. The problem is, once I went to connect the new switch I realized it was not as simple as I thought. There are three sets of wires. Long story short... I've tried every connection possible that makes sense, but clearly I'm missing something. Attaching the photos here. The middle set of wires in the connection box (see second photo) are the ones that seem to have the power, since certain combinations with those specifically cause a trip to the breaker. Anyone have any idea how these should be connected? photo 1 - this is the broken smart switch I replacedphoto 2 - this is the connection boxphoto 3 - this is my new dual switch

  • Can you post a photo of the inside of the fan box please? Commented Aug 20, 2019 at 4:11
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    Never again play "hookup roulette" like you did. You will chance upon many ways to hook up wires which will work but will kill you. Always stop, use logic and/or get help. You may have noticed wires are not color-coded by function. The information about what the wires do is recorded positionally by which wires are connected to what. In your wild groping around, you have destroyed this information, which makes it a much harder problem. That's the other reason not to do it again. Commented Aug 20, 2019 at 5:32

3 Answers 3


The old smart switch is not capable of controlling a fan and light separately... and you never claimed it did. That means your 3 cables are

  • Supply (always-hot)
  • Onward (always-hot) power to something else
  • (Switched-hot) power to the fan/light

First, all grounds get nutted together with a pigtail that you'll need to buy, and get pushed into the back of the box (except the pigtail, bring that out!)

Second, all white wires get nutted together and pushed into the back of the box. These are neutral. You don't need a pigtail here; dumb switches don't use neutral.

Third, that switch goes into the trash. Get a plain single switch.

Fourth, The ground pigtail goes to this switch's ground terminal.

Fifth, get a black pigtail and attach it to one of the screws on the switch. This gets wire-nutted together with the black wire you are fairly sure is supply hot. Feel free to wire-nut this very lightly, you'll be adding to it later. These two wires are called always-hot.

Sixth, pick an unattached black wire. Attach it to the remaining screw on the switch. We are guessing here.

Seventh, power up the circuit and see if the fan/light is starting to work. If both work, awesome, you have identified switched-hot for both light and fan... go to step 8. If neither one works, repeat step 6-7 with the other unattached wire. If only one of them works, power down and repeat step 6-7 with the other unattached black wire.

If one wire works the fan and the other works the light, then you've made a monkey out of me. Fish that double switch out of the trash and follow somebody else's instructions.

If both of them work with one wire attached, then my advice stands. Leave that wire attached and step 7 is done.

Eighth, take the remaining black wire and attach it to the black wires under the wire-nut. This time, crank it down gorilla-tight.

For bonus points, identify the light+fan wire and mark it with red tape. Or if they are separately controlled, mark the fan with red tape and the light with blue tape. You'll thank me later. If you had color coded these wires at the very start of this, life would've been much easier. Colored tape is your friend.


As you have now learned the hard way, always take a picture BEFORE disconnecting any wires. That way (a) you can put things back to the original configuration if necessary and (b) the original configuration can help others trying to figure out what is going on. That being said, the simple setup would be:

  • One set of wires = power in from panel. Presumably the one you identified
  • One set of wires out to each switched load

and in that case, the normal configuration is:

  • Black in wire to common on switch. A typical double-switch has one incoming hot screw. Some will have two, typically with a removable tab to connect them together. If the switch has two separate screws for hot (i.e., 2 hot, 2 switched) then use a pigtail to connect the hot wire to two short pieces of black wire to connect to both hot screws.
  • White wires = neutral = connect them all together with a wire nut. The smart switch may have actually used the neutral, but with a regular switch you don't need it.
  • Black out wires to the other (switched) screws on the switch.
  • All bare ground wires together with a wire nut. Add a short bare or green wire to the ground bundle to connect to the ground screw on the switch.

Assuming set of wires in the middle ( bottom right ) are hot and that you know the other 2 sets of wires go to the fan and light :

Your double switch has 4 terminals on it. Take note that on one side of it there is a jumper which connects 2 terminals together. Let's call that your "hot side". The other side of that switch has 2 terminals on that AREN'T connected together.. Let's call that your (2) switches side.

Note : Insure the power is off before any work is performed

1) Connect the black hot wire (located in the "middle" of your box as you mentioned with pic shown) to the "hot side" of your switch. 2) Connect the other 2 remaining black wires separately to each terminal on your (2) switches side. 3) Connect ( with wire nut ) all the white wires together in the box... To be clear, those white wires only connect to each other and nothing else. 4) Connect ( with wire nut ) all the bare ( non insulated) wires together. Add one additional bare wire to this and connect it to the GREEN grounding terminal to the switch.

Don't install the switch yet.. 5) Temporarily turn the power back on to that circuit.. 6) Check the Fan and Light switches for functionality on /off.

If it's all good, SHUT the power off and install the switch, then turn the power back on, trying one last time. You should be all good with that.

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