enter image description hereRecently, I was replacing a fan switch at the ceiling fan on an older ceiling fan. While I had the power off, I decided to try to correct some wiring at the wall switches. The light switch at wall worked fine. The fan switch is one of those round ones where you turn it to the right or left to adjust fan speed and turn to the left to turn off. What was happening here was the fan speed was not being changed, but the light would brighten/dim and then cut off when you turned the knob a certain direction. The fan and light switches are in separate boxes. The fan switch has 4 wires coming in (from House, to ceiling fan, to light switch, blue wire from ceiling fan to control light. Based on the behavior of fan switch, I believe the wiring was as follows 1. Black Home wire, Black wire from fan switch, Black Fan wired together 2. Black Light and Black Wire from fan switch wired together. 3. White Home and Blue wire wired together. 4. White to fan and and White Light wired together 5. Grounds wired together. This is an older switch, so no ground from fan switch itself.

To correct and make fans switch work properly, shouldn't the black Fan wire from #1 been swapped with Black Light wire from #2?

  • 2
    Hello, and welcome to Stack Exchange. This is a lot of text to parse; a diagram would be really helpful. Jun 19, 2016 at 19:39
  • I've added a diagram to original post. I've left out some detail in diagram because I thought it would make it more confusing. Jun 19, 2016 at 20:17
  • The trick is, hook up one circuit at a time. Hook up the fan, troubleshoot until it works fine, then hook up the light and troubleshoot until it works fine. Jun 19, 2016 at 21:47

1 Answer 1


While the observed behavior does not correspond with your conjectured wiring description -- it does correspond with your suggestion that the fan and light switches were interchanged. Based on your diagram, the following wiring should work:

  1. Black from house nuts with White to the light switch (tag this wire with a piece of electrical tape!) and one of the Blacks on the fan switch.
  2. White from house nuts with White to fan.
  3. Other Black on fan switch nuts with Black to fan.
  4. Black to light switch nuts with Blue to fan.
  5. And of course, all the grounds together.

Last but not least -- I suspect the Blue (probably actually red, but w/e) wire to the fan and the White wire to the fan were swapped at the fan from your description -- the behavior in your description would have the fan running all the time with both switches controlling the light. You'll want to fix that while you're changing the wiring in the fan switch box -- the best way to do so is to go into the fan box and switch the blue and white wires if white isn't to white and red or whatever isn't hooked up to blue.

  • Thank you for your answer. I was comparing what I proposed as the correct wiring (1. Black Home, Black Fan Switch, Black Light) 2. Black Fan Switch, Black to Fan 3. White Home, Blue Wire 4. White to fan, White to Light) to your answer and I was wondering would the wiring I proposed work? Jun 19, 2016 at 21:11
  • Both switches were controlling the light. Jun 19, 2016 at 21:22
  • After reviewing it some more, I can see why my suggestion wouldn't work and yours would. I wound up disabling the fan switch at wall and just use switch on fan itself. I will be remodeling soon, and I may eliminate the fan switch and have all the wiring going to light switch and have a central thermostat in place of the fan switch. I was wanting to know what to do should I face a wiring situation like this again. I connected black home and black light , black fan wirenutted at end, white home to blue wire, white fan to white light, grounds together. Most of the wiring I left in place Jun 20, 2016 at 1:55
  • . Just mainly changed the black wires. Jun 20, 2016 at 1:55

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