Alright folks – here's my issue. My house has a ceiling fan that worked for a bit when we moved in…then stopped. I assumed the fan itself (a cheaper contractor model) just went bad. I went and bought a new fan to replace it. The fan is not wired as a switch loop – the power goes into the switch box, then to the fan.
The room itself is wired as follows:
Power to the room > outlet > outlet > outlet > outlet > junction box > switch > fan. The other wire from the junction box goes to another switch > wall sconces.
All outlets work, as do the wall sconces. On every outlet, Hot-Ground=~120v, Hot-Neutral=~120v, and Neutral-Ground=~0v. Resistance from Neutral-Ground=~0.
In the switch box that controls the fan, the Hot-Ground=~120v and is connected to the switch. The Neutral wires are connected to each other and read ~20v to ground. Resistance between ground and neutral is high/unreadable. At the fan – the readings are identical to the switch box. And finally, the initial indicator of there being a problem, the new ceiling fan will also not work. (I tested this new fan on a known good circuit, and it worked.)
My thought is going to a loose neutral. However, while I understand the concept, I don't fully know if my problem points to that or not. It would seem to me if it is a loose neutral, that the logical first place to look would be the junction box right before the switch. I did confirm that the neutrals connected in the switch box are well connected and tight. Anything else that stands out to people smarter than I?
Other tidbit – I have no idea how they wired the outlets – either with the stabs, or (how I think is more correctly in this situation) using the terminals and wire nuts.
UPDATE/FIX: While I never actually saw a loose neutral to confirm – that was the ultimate culprit. I checked the outlet right before the junction box, and it was indeed back stabbed. Pulled it out, and replaced it with a new receptacle (with child protection,) and pig tailed. That did not take the voltage out of the neutral at the fan/fan switch. I then opened the junction box, and pulled all the wire nuts off, and resecured them (better) – no more readings at the fan box. So – something in that junction box was the culprit.
Best Answer
Check the last receptacle before the switch, anyway
This sounds like a failed connection at the load-side neutral of the last receptacle, given the voltage readings observed. My bet is that the receptacles were wired using backstabs, too, so if you pull out the last receptacle in the chain and find it back-stabbed, I'd change it over to pigtails to the side-screws, and then repeat for all the other receptacles in the house even, one circuit at a time, as builder-grade backstabs have a habit of stabbing folks in the back in the way you see here.
The other place I would check would be the junction box. A wirenut is less likely to fail than a backstab, and the lights aren't going to be nearly as susceptible to brownout as a ceiling fan is (the ceiling fan starting current is probably causing enough voltage drop across the bad connection that the fan simply does not turn, while the bulb's simply going to be a bit dim at most), but it's worth checking while you are in there.