I have two sets of three way switches. Two of the three way switches run to the same box. It appears that the power source is coming into the box to power both three way switches, but I can't seem to get the power to power both switches without having the lights always stay on or somehow not being able to power both. I have wired one switch in and I had it wired around to power both sets of lights. I have thought that I might need a four way switch, but I'm not sure.
Harper's yellow tape is here to rescue you.
All these horrible wiring diagrams are spaghetti. Red here black there AARGH!
3-way circuits are actually pretty simple. It's just they use 4 functions of wire (aside from ground), so color code them with electrical tape and life is better.
Harper's law of marking wires: mark both ends at the same time!
- neutral (white)
- always hot (black)
- switched hot (red)
- 2 travelers (yellow) they do the same thing and are interchangeable.
Wire one at a time.
First wire neutral through from the power source to the lamp. Done. It must use the native white wire.
Second wire always-hot from the power source to one of the switches to its black screw. Use black.
Third wire switched-hot from the other 3-way switch's blsck terminal, to the lamp. Use red and remark any wires that aren't natively red.
You now have left: 2 brass screws in each 3-way and 2 wires in the same cable. These are travelers. Mark them both yellow (really) and attach them to the brass screws.
Or mark them blue or green or whatever color you have. The point is mark them both the same.