In our guest bathroom, we have a fan/exhaust combo with 2 switches. Today my wife noticed that the light wouldn't turn on until she turned the fan on. Then she could turn the fan off and the light would stay on.

Bathroom Switches

I did not modify the switches in the bathroom. Right is fixture above sink (working fine). Left and middle are ceiling are ceiling light and exhaust fan respectively. If I turn on the light and it doesn't come on, turning on the fan makes is work. I have noticed that after I did use it for a while it does actually work sometimes independently of the fan.

Fan model is a Nutone 763 I believe:

Fan and exhaust info

FWIW - I did just add a "smart switch" to a light that was on the same circuit in the breaker box. It seems like it can't be a coincidence, but the light switch I added and all other lights are working fine.

Foyer / front porch switch which was modified:


The two blacks were connected to the previous switch, the bare ground I connected to the green wired switch, and the neutral I connected to the 3 white wires that were capped together.


Switches closer

White wires out of way

For visibility I have moved the middle switch out of the way but it was not modified. Left most is Entryway light, middle is nothing as far as I'm aware, and the right is the Front Porch light I wanted to put the smart switch on.

Thanks for any input.


  • I did have to tie into the neutral. My guest bath, hallway and front porch light are all on the same circuit. I added the smart switch to the front porch. The smart switch, foyer, hallway and bathroom light all seemed fine...Until I noticed this behavior for the exhaust fan and light. – eluno1 Jan 7 '18 at 21:32
  • ah, misundersood. if you turn the light on, nothing happens, you turn on and off the fan, what's the light doing after the fan is off? – dandavis Jan 7 '18 at 21:35
  • Turn on fan light comes on. If I then turn the fan off, the light stays on. – eluno1 Jan 7 '18 at 21:38
  • 1
    Can you post photos of the insides of the boxes, and what is the model number f the fan? – ThreePhaseEel Jan 7 '18 at 23:16
  • Just to be sure I am reading your post right the fan is integrated with a light. It sounds like a wiring issue - are you sure you tied into a neutral and not a hot, I mean you measured it with a meter and did not assume on color code ? Your fan combo may have been wired incorrectly to begin with. Check your switches, you should have 1 hot incoming along with 1 jumper fan to light switch (typically the bottom screws). 1 Out to fan hot, 1 out to light hot (typically the top screw of each switch) then your neutrals wire nutted. also grounds. pictures are helpful, fan make-model.. – Ken Jan 8 '18 at 6:58

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