I am trying to replace a single pole power switch of bathroom fan with timer switch. I tried to connect the wires as per the user manual but the fan works only when it’s connected to the power switch and dose not work with the timer switch. It seems like the fan is wired in a strange way the hot wire go to the fan direct and both wires going to the switch black and red get current when the switch is turned on when the switch is off there is no current in both wires going to the switch enter image description here

The one to left is fan the right is vanity lightenter image description here

  • Is that blue wire just hanging loose in the box? Did you disconnect any of the white wires from the way they were originally? – brhans Dec 25 '19 at 7:52
  • Actually this is the green wire which is connected to the ground. It disconnected in the picture but it was connected before. No i did not change any of the wiring is just replaced the switch with the timer – celina Dec 25 '19 at 14:07
  • Are the fan and vanity light turned on and off by the same breaker at the panel, or by different breakers? Also, what make and model is the timer switch in question? – ThreePhaseEel Dec 25 '19 at 15:32

Actually, the problem was that the fan was three way wired to a random switch downstairs! I just hooked the traveler wire up and it worked!

  • Glad you were able to find that other 3-way switch and lick the problem! – ThreePhaseEel Dec 26 '19 at 1:38
  • Hello, and welcome to Home Improvement. Thanks for answering your own question; that helps future visitors. And, you should probably take our tour so you'll know how best to contribute here. – Daniel Griscom Dec 26 '19 at 13:18

It sounds like a hot and a switched hot were swapped. If this is the case it would answer why the fan will work with the light on but won’t work with the light off.

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