For 3-way and 4-way lighting circuits to work properly, one must pay specific attention to the red and black traveler wires that run between switches. A 3-way circuit will have a 3-way switch at either end of the wiring (I know, that's kinda obvious). A 4-way circuit takes a 3-way set-up and adds as many 4-way switches as you want between the two 3-way switches. 3-way switches will only have one 3-wire cable with red and black traveler wires coming into the box. 4-way switches will have two 3-wire cables with red and black traveler wires entering the switch box. The key to things working properly in any 3/4-way wiring setup is to pay attention to where the red and black traveler wires in a cable are connected at the switch. The rule to follow is that red and black traveler wires in the same cable must go to the same colored screws on the switch.

You probably got the traveler wires crossed up when replacing the switch. Because switches can be built/wired differently inside the switch, putting the wires back in the same position is no guarantee that the switch is wired correctly. Manufacturers don't have to keep the same colored screws at the same locations, there is no industry rule for that. Just pay attention to the screw colors, not the screw positions on the switch.

Your new 4-way switch probably had two brass colored screws and two black screws. When looking at the wires inside the switch box, there will be two separate 3 wires cables coming into the box. The black and red wire from one cable must go to the same colored screws, and the black and red wires from the other cable go to the other colored pair of screws. That should get your 4-way switch working correctly.

If things still don't work (the upstairs switch??), then go to the other 3-way switch and make sure that they are wired with the red and black traveler wires to the same colored screws as well.

Thanks. Unfortunately, the 4 way switch in the kitchen for the hall light has four black wires, two of them with the old hairy covering on them. I suspect that the other switches on this circuit have the same type of wiring. Having color coded wires on these things would be too easy.

The 3 way for the other lights (the only one with different colored wires) was removed last week by an electrician to replace it, then put back when we realized that the one in the box with it was a 4 way, not a 3 way, and since the replacement used a different cover, we couldn’t finish the swap because I didn’t have a 4 way switch on hand. I suppose it’s possible he didn’t put the 3 way back correctly and I put in the new one the same way I found it yesterday. These are not lights that I use daily and I might not have noticed if they weren’t working.

I think I’ll just have the electrician come back and figure it out.

The 'hairy' wiring is just old style cable. If the hairy cable had 3 wires, 2 black and 1 white, just treat the 2 black wires as the red and black traveler wires. It doesn't matter which wire goes to which same colored screw, just as long as the same traveler wires go to the same colored screw.

• Lutron switch installation instructions (diagram #6 wiring diagram)
• 4-Way switch diagram

Here's what I would do:

1. Confirm that you have two 3-way switches and one 4-way switch.
2. Determine which of the three electrical boxes has a wire that runs to the circuit breaker. That electrical box should house a 3-way switch (left-most switch in diagrams).
3. Determine which of the three electrical boxes has a wire that runs to the light. That electrical box should house a 3-way switch (right-most switch in diagrams).
4. Determine how wires run between the three electrical boxes. As shown in the diagrams, the remaining electrical box (that houses the 4-way switch) must have wires that run to both of the other electrical boxes (the ones that house the 3-way switches).
5. Once you've figured out the wiring, follow the diagrams to connect the wires to the switches.

Update: another electrician came out to do some other stuff and I had him look at the switches. The 4 way way just had to be figured out due to the new switch type, but the 3 way was incorrectly wired at the other box by the previous licensed electrician, which was why I was not able to get it to work properly. I was doing it correctly but did not have the skills to troubleshoot the incorrect wiring problem from the other box.