So I'm not the best with electrical work, and I'm running into issues replacing my bathroom vent fan and light.

The setup is three switches on the wall:

  1. One switch controlled fan.
  2. One switch to vent light.
  3. One switch to other ceiling light.

Where the new vent fan and light is going:

  • From the ceiling - two sets of white/black/ground
  • From the light/vent - two sets of white/black/ground

If I connect everything one to one:

  1. The first switch turns on fan and other ceiling light.
  2. Second switch does nothing?
  3. Third switch turns off fan, and makes the other ceiling light brighter.

Help? How should I be wiring this?enter image description here

Update: just attached black to black, and white to white (for all four wires). The fan works, the ceiling light works, but when I switch on the light for the vent unit, both the vent light and the other ceiling light just start flashing. It's like I've wired an alert that I'm terrible at electrical work.

  • Can you post photos of the insides of the boxes please? Jan 8, 2017 at 22:10
  • Added photo of box.
    – apichel
    Jan 8, 2017 at 23:52
  • 1
    Can you post photos of the insides of the switch boxes? Jan 9, 2017 at 0:55
  • 1
    How was the old fan/light hooked up? This seems like a "one step at a time" sort of deal. Jan 9, 2017 at 2:36
  • Can you also provide a link for the vent itself? Most of them have a manual that details the wiring in a diagram.
    – Hari
    Jan 9, 2017 at 19:52

1 Answer 1


Please excuse my MS Paint representation, but it should help. Switch Layout

From what I understand, the grounding wires may not be necessary, but if the fixtures have ground wires or grounding terminals, it can only help to connect them. This question explains grounding in some more detail.

One exception is that if the vent is directly over a shower, it might need to be GFCI protected (see this question). This could be done in a variety of ways. You could install a GFCI breaker and run the vent on a dedicated circuit, but that would be annoying if it tripped since you could only reset it at the breaker. You may be able to install a dedicated GFCI outlet in the bathroom and connect the vent and switch to the protected side of that outlet. You can also find combination GFCI outlet/switches that would combine the GFCI outlet and the switch into one unit.

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