electrical
I ran a new plug into my bathroom from my lights. I secured all my neutrals together and all my power together except for the lonesome black wire that’s running to the switch.
When I reinstalled my light and connected it to the wire going to the switch nothing happened but when I connected it to all the other blacks it turns on but it won’t turn off.
I know I’m missing something and it could be simple or difficult !
Assuming this is the setup you have described:
You will need to pull a new 12/3 cable to your new 3-way switch. You will also have to replace your existing switch with a 3-way switch. Your wiring setup will look like this:
Because your lighting circuit's power is supplied by a conductor in a 12/3 cable, the figures above were modified as follows:
POWER SOURCE / 2-Wire Romex with Ground (i.e. 12-2) - I modified these to show your 12/3 wire with your RED supplying the power to your lighting circuit (since you described the BLACK in your 12/3 as being spliced into a bunch of other black conductors). From here, everything else should be one-to-one.
Yes, the white wire is required for the light built into the switch to work. It does not affect the switching of the bathroom light. You will need to create a pigtail (a short piece [6-8"] of wire connected to the two in the box) to join to your switch.
In you picture, the red wire going to the switch is the load, and the black wire is the hot.
Best Answer
Wire it like this.
Note that not all white wires are neutrals. One of them is part of the switch loop. Once you have identified it, mark both ends of it with black tape or paint.
If you can't tell which white wire is the one going to the switch, it is the white wire that comes into your ceiling light junction box through the same hole, or in the same cable, as the wire you've been calling the "lonesome black wire that’s running to the switch".
If you still have trouble understanding how this circuit should work, get your library to send you a book on do-it-yourself home wiring, and read the section on switch loops.