Help with rewiring 3 way? switch

My friend and I were trying to change outlets and switches on a house they just bought. Seems that there are several switches and outlets on one breaker. Only one switch was changed but it caused everything to stop working. We refer to it as the demon switch. We have tried lots of different combinations but must still be missing the right one.

See attached picture. I try to highlight the black wires with darker black. There are a couple of wires that don't go anywhere (LR, two connections only have black wires, the whites are cut off very short). The Living Room only has a single exposed white wire (barely visible on right side of box).

Only the Living Room (far left) has been changed (aka the Demon Switch). The two hallway and bedroom are the same they have always been. I also mentioned there are several plugs on the same circuit. Every combination of wiring we have tried results in the plug tester showing "gnd neutral reversed". Other online research says this may really mean "open neutral".

We didn't have a continuity tester with us so I am not sure where some of these wires go. The two hallway switches should go to a light (not shown). But I am not sure how that is connected.

With that background, my questions are:

Do the connections on the other three boxes make sense in any way? If they make plausible sense, then how should the demon box be connected? And I assume that should be a three way switch?

 

Welcome to the forums.

Looks like a lot of confusion here.
Make sure you identify future wiring when you change devices.

The two hall switches look like three way switches. Remember...... there is a dark colored screw on a three way switch. Make sure the same wire goes back on the dark colored screw. Do not go by position on the switch.

You are showing three black wires on the LR switch. One is the hot, one is a feed thru to your receptacles and the third one is whatever is switched. That means that two of those black wires need to be connected and then to one of the switch screws. The remaining black goes on the other screw.

However I am concerned about the cut short white wires. That doesn't make much sense.

 

Thanks. Look forward to the forums as they seem extremely helpful.

On all the other switches we had changed (no other ones on this circuit) things went fine and it was easy to keep track of what was where. The problem with this switch was that it had a couple of push type connections and a couple of connections screwed to the terminals. The replacement switch could only accommodate screwing to the terminals. We also tried to just match up locations. This is really where we must have errored.

We labelled the four wires in the LR box. A and D are the black wires that have the white wires snipped short. B is the white wire in the other conductor and C is the black.

It was pretty easy to tell that D was the hot always. We knew to get power to the rest of the items downstream we would need to get that wired to them somehow. We were not clear about A. I wasn't sure if it was just used as a traveler or what. It didn't make sense. What we did try for troubleshooting is just connecting with wire nuts the various combinations of A,B,C,D. None of those seemed to get us anything right downstream.

How to know which two black wires would go together on the 3 way? And I assume they would go to the common. I assume one is D/hot but the other one?

Remaining black goes on the "other screw" but there are two more screws on a 3 way. Were you assuming a 2 way instead? Plus, what to do with the single white ?

If it helps, we could care less about this LR switch right now. Would that make it easier to get the downstream devices working? Surely we need to tie the D/HOT to the bottom pin on the Hall1 3 way switch? Would we assume all the neutrals are just worked out from there? We were getting the possible "open neutral" on the outlets downstream.

 

For future information these are usually a splice between two wires, the wire in the back stab and the screw that corresponds to the back stab. As you remove the two wires connect the two wires to a pigtail. Here we recommend never using back stabs because they are unreliable. Using as splice points is another use that as you found is not a good idea because it leads to confusion. Normally the screw associated with the back stab is the nearest. That can be verified with a multimeter set to ohms.