Hi All,

I currently have a ceiling fan controlled by 2 toggle switches. I was hoping to replace them with a dimmer switch for the light and a speed control for the fan.

The left switch controls the light, but I can't figure out what the right switch does? It doesn't control the light or turn just the fan on/off. It just doesn't seem to do anything? So, I was wondering if perhaps someone could tell me from a picture of the wiring here what it does?
<img src="https://i.imgur.com/PDrWtbT.jpg" width="1280" height="1920"/>
Basically, the right mystery switch has only 2 wires connected to it...a red one from the box and a black one just connected to the left switch. So, what's going on here?

And if I want to add a light dimmer switch and fan speed control switch...how should I do it?

Thanks!!!

 

Not only do you have a mystery there...... you have a mess.
I'm seeing one white and three black wires on one switch terminal.
I'm seeing two white wires twisted together with no wirenut.

Your left hand switch is wired as a switch loop except that power is starting at the switch and not at the fan.

Do you have any bare copper wires connected with the two white wires ??
It looks like the ground wiring is being used as neutral.

We would not have any way to tell you what the right hand switch controls.

 

^ Yes, 1 hot mess! But maybe I'm missing something, because in the other bedroom, the right switch also apparently does nothing, either. (I haven't opened it up to see if the wiring is the same, though.) But, there must be SOME reason they were installed like that???

And no, there are 3 wire bundles coming in, with all 3 bare (ground) wires simply twisted together.

The white (neutral) wire from bundle #1 is connected to the switch terminal on the left switch, and the 2 white (neutral) wires from the other 2 wire bundles are simply twisted together (with no wire nut).

Here is a view looking upwards that shows this configuration better.
<img src="https://i.imgur.com/bETrB0t.jpg" width="1920" height="1280"/>
And here's another view looking down for another angle:
<img src="https://i.imgur.com/qyYNCJB.jpg" width="1920" height="1280"/>
Sorry, I'm an electrical noob here. What is a switch loop?

 

Also in your first picture it looks like the insulation on the red wire was nicked when the cable jacket was cut. You should put some electrical tape (or shrink wrap) on the cut area to prevent future problems.

And the wires in push-in terminals should be moved to the screw terminals since push-ins are more likely to cause problems.

 

On your left hand switch.... there are 4 wires connected to it. There is black all by itself and there is one white with two blacks.

White is always used as neutral except when it's used as a switch loop. To explain a switch loop..... the power would come into the light or fan. That incoming cable would contain the neutral for the device. Then the hot is sent to a switch on the white wire and it is returned..... switched..... on the black wire.

In your case..... the white and black wires from one cable is connected to the switch. That would indicate a switch loop. But then power is also put on the white wire on the switch. That would mean that the white wire was getting power at the switch and that there is a different neutral used at the fan/light.

This diagram illustrates how a typical switch loop gets wired.

 

OK, so it's called a switch loop because the function of the black & white wires get switched? As in, normally they are (respectively) hot & neutral...but they get switched around the light switch to neutral & hot?
<img src="https://www.thespruce.com/thmb/0ktreCdktE2GPRRisMbivWpQEzw=/1500x0/filters:no_upscale():max_bytes(150000):strip_icc():format(webp)/color-coding-of-electric-wires-1152300-FINAL-5bbcc3f846e0fb00265e6788.png" width="1500" height="1000"/>
<img src="https://i.pinimg.com/564x/4f/96/c8/4f96c8bc22a63223994b3523ca036645.jpg" width="563" height="474"/><img src="https://i.imgur.com/GCm4ldQ.jpg" width="550" height="618"/>
It also seems that typically ceiling fans use 2 cables...so why does mine have 3???

 

OK, so I went ahead and installed a light dimmer switch on the left, and a fan speed control on the right. I tried to just rewire them the way the original toggle switches were.
<img src="https://i.imgur.com/QMY4qf2.jpg" width="1280" height="1920"/>
So, the light dimmer switch on the left works, but the right switch doesn't do anything, just as before. The rightmost "Romex" cable #3 it connects to does seem connected to one of the outlets in the room, though. Because when I had initially left the hot source wire from cable #2 disconnected from the speed control, then that 1 outlet didn't work anymore. And as soon as I connected it to the speed control, then that outlet worked again.

So, it seems that I've now "successfully" replicated the initial wiring, with the same results. The left switch controls the fan light, and the right switch appears to do nothing, other than close the circuit for an outlet in the room.

Here's a new problem though - I just noticed that my water heater downstairs isn't working now. No hot water. However, it has a separate breaker on the circuit breaker panel. Does this mean that it is on an entirely different circuit, and thus could not have been affected by my rewiring here? And it just "broke" coincidentally now? Or is it possible that I broke its circuit or messed it up somehow???

 

If the left switch is a switch loop..... there should ONLY be the white and black wire from cable 1.
It looks like cable 2 is hot and neutral in.
That would make cable 3 the three wire cable to the fan.

I cannot not figure out what the additional feed wire is connected to the left switch.
It almost looks like something lost a hot and they are jumping it there.

You need to confirm that cable 2 is the hot feed to that box.

There should be no correlation between those switches and your water heater.

 

Well, yes...so the cables have:
#1: 1 gray, 1 white, 1 bare ground (I believe both gray & white were weakly hot)
#2: 1 black (main hot source that I put a small white tag around), 1 white (neutral), 1 bare ground
#3: 1 black, 1 red, 1 white, 1 bare ground (none of these were hot)

So basically, the main hot power from #2 comes in and splits into the black wire of each switch.
But, the (switch looped?) #1 white wire also ties into the left switch's black wire, and the (switch looped?) #1 gray wire then ties to its red wire.
The #3 black wire also ties into the right switch's black wire, and the #3 red wire ties into its red wire.
The white wires from #2 & #3 are still pigtailed together.
Both red 3-way installation wires from the switches hanging out in front are left unconnected.

And I labeled the pic above to help clarify this all better...

And hmm thanks, maybe it's just a coincidence my water heater went out, too? Guess I'll need to head over to the plumbing subforum here next...

 

If you are using a non contact tester..... you may find weak signals on dead wires. An analog voltmeter is the best choice for testing circuits like this.

Do you know what cable 1 is for ?
As mentioned.... if it is a switch loop.... it doesn't get power at the switch.
Since you're getting basically no voltage on cable 1..... it would stand to reason that the left switch should get power from that box and the white wire should be on the neutral splice. Sending hot out on both cable 1 wires makes absolutely no sense.

Try pushing the water heater breaker all the way to off and then turn back on.
Next step would be to check for 240v at the top thermostat in the water heater.

 

^ Yea, it makes no sense. I could never figure out the intent, but it only seems to work when I rewire it the same...

Anyways, yes, the water heater simply broke down at the same time I was rewiring those switches by pure coincidence/Murphy's Law!

So first I tried turning the breakers on/off...but that didn't work. Then I tried hitting its reset button, which also didn't.

After that, I just called a plumber...who quickly determined that the element went bad. However, it also turned out that my heater was 23-yo! Which was about ~13 years older than the average lifespan! So, I decided to just buy a new one before the whole old one wore out, rather than sink any more money into repairing it.

I eventually found a hopefully-decent, glass-lined replacement from Ace Hardware. Regardless of brand or model tier, it seems like glass linings help stop leaks, although they do have to be more careful when delivering them. The other key factor when selecting a new unit was making sure to get one to fit within the old space, which eliminated many others right off-the-bat.

Finally, you're also supposed to get a permit from the city for the install to make sure it and your water pressure are up to code. I actually have to get a PRV installed to lower my water pressure now, too.