I have replaced all electrical outlets and light switches in my home. All are working except 4 light switches. 3 are together: a single pole that controls foyer light, a single pole that controls porch light, and a 3-way that controls outside lights. The corresponding 3-way for the outside lights (that is in a different area) is the 4th one that is not working. I have checked the wiring and the breaker, all is OK. Any troubleshooting ideas?

Got to be a wiring issue. Probably used jumper wires. Make sure they are all tightly connected. Also be sure neutrals are wire nutted tightly.

Used existing wires, attached to new switches exactly as they were attatched to old switches.

Have you checked voltage or continuity? You have a loose or misconnected wire somewhere unless the breaker has not been reset properly.

Quote:

---

3 are together: a single pole that controls foyer light, a single pole that controls porch light, and a 3-way that controls outside lights.

---

Describe the wiring in that box. Describe the wiring in the other 3-way switch box.

Do you have a meter?

There is a kind of voltage meter that I like and I think may help you out here if you do not have a test meter yet...
It's about the size of a large pen and may only cost $10. All you need to do is hold it next to a "live" wire and the pen turns red and chirps!
Used carefully we can test and check enough to get moving in the right direction, at least we will know if the circuit is live...

Could be in that switch box, or a receptacle nearby as well.
The 3 single switches need constant power and tied together, see what is tied on with those 3 switches and see if the wiring goes up, down or out the side to help locate the source.
If you had a tone generator and inductive amp, you could place a tone on the switch hots and listen for the tone at each box and at the panel.
Breakers can trip, but not throw.