Take over a mystery switch for fan on/off?


I tried a smart fan control for my large Hunter 3 speed ceiling fan. The speeds were messed up, and I read where these smart fan controls are not compatible with all fans.

So as an alternative to controlling my fan speed, maybe I could do an on/off. There is a mystery switch right next to my old fan control. I have no idea what it does, seems to do nothing. So I was thinking I’d replace the old mystery switch with a new smart switch and would take the load from the new switch and put it to the line of the old fan control.

Seem like a good, or bad, idea?


the mystery switches next to my fans were all wired for the light kits that were not installed, since the rooms had can lights. I used enerwave 7 button switch there since it was available with power. For my fans, I just the GE smart fan switch and leave the fan at max and then use smartthings to dim the fan to high, medium, and low. Good luck.


In my house there’s this light switch that doesn’t do anything. Every so often I would flick it on and off just to check. Yesterday, I got a call from a woman in Madagascar. She said, “Cut it out.” - Steven Wright

(Ray) #4

In my experience. Most of the time the mysterious switch is usually for controlling a receptacle plug where you plug your floor/table lamp. It was very popular in older home. But yeah, sometime it’s for people from some island half the world away too.


I was using a Wink hub at the time when testing my smart fan switch. The dimming sorta worked, but what I got was High=SeemedOk, Med=TooSlow, Low=WayTooSlow. All the dim settings in between didn’t change anything. Someday I’d like to figure out a fix.

(Don) #6

I would make sure you have a switch made for ceiling fans like this one I’ve used:

Make sure you get it wired correctly and set your fan pull switch to HIGH (don’t ask how I know that part)
Once that is working I would install and use this custom device type instead of the default. This one will give you a low,med,high button in your smartthings app instead of the slider control.

I hope that helps. It’s worth the effort once you get it working.

(Don) #7

There is still only low, med, high.

For a standard fan out of your local big box store that’s all you’ll get. Yes there’s a nice slider. But actually (I understand ) the slider is really only 3 sections.
Say below 33% equals low.
From 33% to say 67% is medium.
Above 67% is high.

Sorry no linear scaling like the image would represent.


That is the one I used. I experimented with the pull switch in all positions, the wall settings, the dimmer settings etc. I see several other reviews on Amazon with the same issue as I had. Not very common problem. I did see one of the others mention they had a large ceiling fan.

(Don) #9

What was controlling your fan speed before? Just on / off switch and pull chain? Or something else? I know the answer is probably NO, but is there any parts of it still in the circuit?

Just trying to help you get what you wanted.

When you say large fan are we talking over 60 inches? Or even 72ish? There’s other’s much smarter tan me in electrical stuff maybe we cam get them to chime in.


It’s pretty close to this. I never touch the chain (except to test). The fan in hanging down from a vaulted ceiling around 3 feet. There is only a short chain. It’s not mean to be controlled by the chain.

I removed this and put the smart fan switch in. When that did not work, I put the old control back in.


Fan looks similar to this one, but hangs way down.


I actually have 2 of those switches, this topic has piqued my curiosity again lol. Ours is an older home.

(Don) #13

Hey @JDRoberts
Can you pull sone wisdom out of your all knowing crystal ball and help us out here. Or tag someone you think can help?

I’m running out of ideas. I know was a short trip there to me running out. I swung and evidently missed.

(Don) #14

I have read where OLD fans could have issues. Where others say HAVE to have right switch for Hunter fans. I am also curious as to why? Always like to learn something new.


Probably a TRIAC issue. Some old fans used a custom step down device that probably wouldn’t work with anything else. You just have to read the specs on the fan and then get a switch that matches those.

@Navat604 or one of the other electrical experts may want to chime in.

(Don) #16

Thank you sir.

(Ray) #17

What you have is a capacitor fan controller. The fan switch is changing the speed of the fan by changing different capacitor to a single tap motor. It’s the reason why you won’t get the right speed with a smart fan controller. You will need the controller in place for proper speed but you can control the fan with a single speed by having the smart switch on/off power to the controller with an in wall relay module such as Aeon, Monoprice or emerwave.

(Don) #18

So @harryman sounds like your original plan was a decent idea. I like @Navat604 idea of the controller being an in wall relay.

(Charles) #19

@Navat604 or @JDRoberts Maybe one of you can help me recover from an old mistake. I inherited a remote-controlled fan/light that I wanted to instead control with ST and the 12730. So, being ignorant to the ways of fan motors, I ripped out the remote receiver and all the electronics; my thinking was that if there was nothing but 120vAC going to the motor, it would be at max speed and the 12730 would then regulate it.

I’m sure you’re way ahead of me: With no switch involved, just pure house current, the fan is at some low speed. Is this fix-able? Thank you.

(Ray) #20

There are quite a few fan controllers out there so if you can provide a little more detail and see if we could figure something out. Try getting these if possible. Fan made, model. How many wires from fan to switch. How did you wire up the smart switch to it. Remote made model. Etc.