3-Way Switch Replacement

I did what should have been a simple project -- swapping out two old three-way switches for two new ones. (The old ones were quite old and dirty-looking, but they worked just fine.)

My problem is, no matter how I wire them, the best result I can get is one switch that works as a three-way, and the other only as a two-way. When the "two-way" switch is in the off position, the three-way stops working. (Yes, they are both three-way switches.)

Every other wiring combination either results in no power at all, or a short circuit.

What am I doing wrong?

 

tell us what you have wire wize at each box (color and number) what is on the switches and where (three way switches have three screws one of wich will be a different color or it will be marked common) how is it hooked up?

 

If you are sure you are connecting the same three wires that were connected to the old switches to the new switches, then you'll get there by trial and error. Unfortunately there are 36 combinations. Keep good notes so you don't end up trying the same one more than once. You'll get good exercise walking back and forth to the breaker panel. Patience is all it takes.

Although there are 36 combinations, reversing the two travelers is not significant. So it really only makes a difference which wire is connected to the common (i.e., black) screw on each switch. So there are really only 9 combinations. Murphy's law says you'll get it on the 9th try.

If you are getting a short-circuit, then you are either (1) making sloppy connections, (2) repacking the box without sufficient care, (3) connecting something other than ground to the grounding screw, or (4) not connecting the same three wires that were connected to the old switch.

 

John,

This house is 20-plus years old, and the wiring is confusing at best.

In what I assume is the master switch, I have three wires -- two black, one red.

One red goes in the bottom of the switch. The placement of the two black wires becomes obvious -- one way works, the other way doesn't provide any power at all.

In the second box, I have three black wires, and one red one. Again, I put the red wire in the bottom of the switch, leaving me three black wires to play with. Obviously, one has to go back to the master switch to complete the circuit.

Which one, I suppose, is the question.

Perhaps I've missed some combination. I'll try again tomorrow when I'm stocked up again on patience.

 

There's no such thing as a "master switch" in a 3-way setup.

Are there any white wires present?

The fact that you have four wires at the second switch presents a mystery. Are you sure this wasn't a four-way switch? If not, then one of those wires is likely pass-through power to something else.

 

Can you put the old switches back and make it work? The screw postions on new 3ways are not always the same as old 3ways. If you can get it to work with the old switches then you should do that and replace one switch at a time. Get the 1st new switch working properly and then change the 2nd one. There are only 3 way to connect up the new switch.