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On the wall we have a switch for the fan and a dimmer for the lights on the fan. The fan works great -- no issues. The lights randomly stopped working today, though.

Now when I open the the part that had all the wires for the light fixture it had 5 black and 5 white. The light fixture has 4 lights so there is one wire for each light and one is the hot wire coming from the top. Now when this wire isn't connected to anything it shows as hot, but once I connect it to one of the wires going to the light bulb it stops showing as hot. It's like it's grounding it or something. This happens to all of the black wires, if the hot wire touches any of the other wires it stops showing as hot. All of the white wires are still connected together.

Any ideas on why the hot wire stops showing as hot when it connects to the other black wire?

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  • I's kind of hard to picture that. hot wire that stops being hot could be normal, could be a fault. – Jasen Dec 31 '16 at 9:18
  • The hot wire is being pulled down through the light bulbs suggests it is high impedance. Suggests that the dimmer is faulty. Try replacing it with a switch and see what happens. – RoyC Dec 31 '16 at 9:44
  • Can you try putting an AC ammeter between the hot wire and the 4 black wires to the lightbulbs? – ThreePhaseEel Dec 31 '16 at 16:17
  • Also, what tool are you using to determine the "hotness" of a wire? – ThreePhaseEel Dec 31 '16 at 16:51
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That's easy. The problem isn't in the fan at all, but rather in the dimmer switch (on the wall, probably).

Most modern dimmers use a kind of transistor (a triac) to regulate the amount of power (and therefore brightness) flowing to the lamp. Those triacs do fail eventually, and when this happens they normally fail "open" (off).

These dimmers will still allow a tiny bit of current through. Not enough to light a single light bulb, but enough for a sensitive voltmeter to detect. If you disconnect the light bulbs and measure the voltage, you'll get close to the normal 120 VAC; but even a single light bulb will "sink" the tiny bit of current leaking through the dimmer, and the voltage drops to near zero. (You could have done the same test by just unscrewing the light bulbs and testing the contacts in the bulb sockets).

Note that for some electronically controlled fans, the dimmer electronics can be in the fan housing and not in the wall switch. This would be particularly true for fans with a wireless remote.

Replacing the dimmer will almost certainly fix your problem. (If you want to test the hypothesis before buying a new dimmer, you could bypass the dimmer, which will, if everything else is good, result in the lights being "on" all the time).

Obviously, make sure the breaker is off before doing any of this.

  • So I replace the dimmer with just a normal light switch and I'm still having the issue. Now when I remove all the bulbs and test the bulb socket I get 125v on all the light stocks, but once I screw in one light bulb all the stocks go to 0v. So does mean something is broken in the fan housing? Is there a way to get see how strong the current the wire is getting? – Travis Cherry Dec 31 '16 at 17:58
  • I found the problem. When I remove the whole light fixture you could smell the what the problem was. imgur.com/a/dOQne. Now do you think it will be safe to just getting a new light fixture or a whole new fan. What would of cause this to happen? – Travis Cherry Dec 31 '16 at 18:20
  • A replacement light kit would be good, however, you need to find one that is similar to what you have. Some light kits are just 2 wires some are like you have and contain all the switches for the lights and fan. Its hard to see from the image what exactly melted. It could be the light pull switch, in which case you can just replace that with a new one. – Jeff Cates Feb 1 '17 at 3:15
  • That still sounds like what I thought it was-- but your dimmer (electronics) are in the fan, not the wall. Think of the wall switch as more of a "remote control" for an integrated dimmer within the fan, in that case. The burned smell will be from the circuit board that needs to be replaced. You may be able to replace that part for less than the cost of the entire fan; check with the manufacturer on that. – Russ McFatter Feb 2 '17 at 13:50

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