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Jnagy · Jan 31, 2010, 07:22 PM

I moved a three gang box that controls the light/heater/exhaust combo in my bathroom which required me to extend the wiring, I didn't change out the fixture and everything in the breaker box is the same. I thought I did a good job of getting it put back together until I tested my set up. The light works, the exaust works, the heater works... here is the catch. When I have the light on and then turn on the heater as well, the light turns off. I've been reading around on the net and it seems most set-ups have a 12-2(which seems like the feed) and a 12-3 to control the fixture. However, what I have is three 12-2's, the home was built in the early '80 in Texas. On one 12-2 set I have a black wire that runs to the bottom of each of the three switches in a daisy chain fashion, the white is tied to the white of the second 12-2 set, the ground is tied together with the grounds of the other two 12-2 sets. On the second 12-2 set the black goes to the top of switch #1 which controls the exaust. On the third 12-2 set the black goes to the top of switch #3 which controls the light. On the same third 12-2 set the white wire goes to the top of the second switch(which controls the heater) and seems to be what is causing the problem. Is there something easy I am missing here? Can this be solved using a different switch? Or should I just hook up the exaust and the light to work on the same switch, cover up the third gang and be done with it? I hope I explained this correctly. Thanks in advance!

hkstroud · Jan 31, 2010, 09:15 PM

Chances are that you have the white wire that is the neutral going to the fan/light/heater mixed up with the white wire that is a hot to the heater.
You know that the white of the cable 1 is the neutral coming to the box because the black of that cable powers the switches. One of the other two white wires is the neutral going to the fan/light/heater, but which one. The remaining white wire is a hot leg to the heater. You need to insure which white wire is the neutral to the fan/light/heater and which is the hot to the heater.

Jnagy · Jan 31, 2010, 10:34 PM

So if this was the case each function would work individually but not together? Can I use a voltmeter to find the white wire that is "Hot"?

hkstroud · Feb 1, 2010, 06:18 AM

You said that you had to extend wiring. How did you do that? Did you replace all the wiring between the fan/light/heater and the switch box or did you replace the wiring between the breaker and the switch box? How many cables in the fan/light/box? Trying to determine if cable 1 is truly bring power to the switch box or if it is just a switch leg?

Try reversing white wire 2 and 3. Most you can do is trip circuit breaker.