I am replacing an existing single switch and a 3 way switch in the same box with one power source. I got everything to work fine.. but there is a wire somewhere that is not right. These lights along with my garage lights/door are on the same braker. When I get the light switches to work the garage lights/door do not. I have 4 blk 2 red 4 white (all together with wire nut) 2 ground, one for each switch. Can't figure out which one is mixed up. I know my hot wire there is only one. Help!

You need to be more specific about which lights are controlled by which switch.
Best guess from the limited description is that you mis-wired the 3 way switch.
The fact that both are on the same breaker most likely doesn't have anything to do with the problem. Did you make a record of which wires were removed from which screws on the old 3 way switch?
This link may help you sort out the problem:
Three-way Switches - What are Three-way Switches

You apparently have two 2-wire cables and two 3-wire cables in that box.
Well, tell us which one is hot.

Try to be a little more specific in your descriptions.

Does that mean that you have an interior light on the 3-way switch and an exterior light by the front entrance and garage lights on the same circuit. Is there another 3-way switch for the interior light?

If the hot wire is in a 3-wire cable make sure that it is a constant hot by moving the other 3-way switch to the other position.


Tell us all you remember about the original wiring. Was there, or is there any pigtails or jumper wires (short pieces of wire) in the box.) If so they would have been connected to the hot and to each switch.

Do you remember the colors of wire connected to the single pole switch, two blacks or a black and a white?

Re-describe being as specific as possible. I'm not there to see things and I have a wild imagination. You would be surprised how many ways I can interpret what you say.

Which switch are you trying to replace? Did you disconnect everything or just some of the wires.

Both switches I'm trying to replace and I took everything apart! Wires coming down from top left are black hot wire, red wire, ground wire and white wire. Wires coming up from bottom left are ground, black and white. Wires coming down from top right are one black, one white and a ground. Wires coming up from bottom right are one black, one ground, one white and one red. That is the problem, I took it all apart and can't remember. I do believe there was a pig tail of all black wires. I do remember one of the white was used as a traveller I believe. But I have put it all back as all white together with wirenut, one ground to each switch on green screw. The single switch is good with the hot wire piggy tailed between the two switches and the red on the other screw of the single switch. It seems I have too many black wires left for the 3 way switch. The red is on the left of the 3 way switch where there is only one screw. The hot wire on the black screw lower right (piggy tailed with other switch). And the black wire coming from the top right (same Romex as the red) above the black screw on the right as a traveller. I am left with 2 black wires left over. Is it OK to double up the xtra black wires on the screws on the 3 way? Will that work? This 3 way switch controls two lights together at the top of the stairs. At the bottom of the stairs I have a 3 way switch with one black which is the hot screwed into the black screw, one red mirrored with the other 3 way switch screwed to top left, one white (this is where I think one of the whites is used as a traveller but which on at the other 3 way and what to do with the black if the white is used?) which is screwed into the last screw above the black screw. I have gotten as close as everything working except the top of the stairs switch. If I turned the light on from down the stairs and hit the other switch at the top of the stairs nothing would happen. Now I'm thinking I need to reverse the switches. I can't remember if the three way was on the right and single switch on left or vice versa. The single switch works the light it's suppose to where it's at now which is on the left of the 3 way. Mind you I separated all wires and tested all of them. Only the one black wire is hot.

Well you sure made a mess out of this didn't you.

Help me out here.

You said,
Is that in a 2-wire cable or a 3-wire cable?

These switches (that you are working with) are at the top of the stairs correct?

Do these stairs go up or down?

The light fixtures are in the ceiling, correct?

Have you messed with the switch at the bottom of the stairs?

How many switches are in the box at the bottom of the stairs? Just the 3-way for these lights or is there another switch there?

How many cables and what kind are in that switch box at the bottom of the stairs?

(We have to talk cables not wires. A wire is a single wire. A cable is two or more wire in an outer covering. There are 2-wire cables and 3-wire cables. We do not count the bare ground wire. Where a cable comes into a box, top, bottom, left or right means nothing.)

You said,
Does that mean the garage lights and the garage door do not work? Or does it mean that the garage lights do not work and a light out side the front door does not work.

Answer each of these questions, be sure and answer each one, then I'll have more.

Paint me a picture of the area we are working with. Like this.
(You come in the front door, there are stairs going up. There are x switches, one for exterior front entrance light, one for foyer lights. At the top of the stairs there are 2 switches... )
OR
(You come in the front door, there are stairs going down. There are x switches, one is for xxx, one is for yyy... )

A little mess! I'll answer in order

- 3 wire cable. Red, blk, white
- top of stairs, yes
- down
- yes, one recessed light at top and one hanging light from ceiling at bottom.
- replaced bottom stairs switch with 3 way, but only 3 wires in there from one cable. I put the wires back in the same locations as the old 3 way.
- Only one switch at bottom of stairs (3 way)
- ground, red, black and white, sorry 3 cable
- garage lights and door (I've wired these switches in every way imaginable. I came close a couple times. With one of the ways I wired the 3 way switch the garage lights/door wouldn't work)

- you walk into an entryway with the stairs to the main living space right in front of you. As you walk those 3 steps toward the stairs there is one light switch to your right as you take that first step up. When turned on it lights the hanging entryway fixture and at the very top of the stairs one recessed light. When you get to the top around the corner on the right you will find 2 switches. One will turn off the light you just turned on from the bottom of the stairs and the other will turn on and off one single hanging light for the eat in kitchen.

The circuit breaker that you use to turn the power off, is it a single breaker or a double breaker. A double breaker can be two breakers with the handles ties together of it can be a double breaker (takes up the space of two breakers) with a single handle?

Single breaker 15 amp.

The hot being in a 3-wire cable implies that cable is used to carry two circuits sharing a neutral. Present code requires that a double breaker be used, so that when one circuit is turned off the other will be also. That has not always been a retirement so that it is possible that you have two independent single breakers.

Do you have a breaker labeled garage?

Do you have a tester and if so what kind.

I apologize. I do have two single breakers. One 15 and the other 20 amp. I have a Klein voltage tester. In the box there are two sets of 3 wire cable and two sets of 2 wire cable.

Strange, I would have thought they would be the same amperage.

That's a no contact voltage sensor, looks like as pen, correct?

Turn off breaker, disconnect the wires in the 3-wire cable you found the hot black.

Check for voltage on both the black and red wires. Be careful, I suspect the red is hot.

The voltage sensor works by sensing the magnetic field surrounding wire. Separate wires so that you don't get a false reading.

Yes a pen. Red beeping and flashing when hot. Green when not. Only one hot and that's the black wire. No red wires are hot.

Not logical.

Are both breakers on? Note a breaker that has tripped may not be apparent visually. Press on the handle toward the on side to see if it feels spongy, or turn off then back on to insure that it is on.

Or just reset both breakers and test again.

Both breakers are on and not tripped... believe me I have been up and down those stairs and turning on and off the breakers quite a bit. That's why I was wondering if there's a switch leg somewhere. I vaugly remember disconnecting a white wire from one of the screws on one of the switches. The 3 way switch at the bottom of the stairs is wired with each color (red, white and black being on the common screw). I am not using any of the white wires for the 3 way switch at the top of the stairs. Could this be an issue?

OK, not apparently two circuits sharing a neutral.

Only other possibility is that power is being taken to one of the light fixtures. From there a 3-wire cable is run to the switch box. The black is bringing power to the switch box the red is returning power to the fixture itself. The white is neutral of course.

Connect the hot black to the red in the same cable and turn breaker on. One of the lights should light or the garage lights/door should work.

OR, breaker will trip.

The light that came on is for the single switch which controls the eat in kitchen light. That's the only switch I could hook up correctly.

Now we are cooking with gas.

Power comes to that kitchen fixture box. From there the 3-wire cable brings power and neutral to the switch box. The black is power in, the red is returning power to the light fixture itself.

The other 3-wire cable is for the 3-way switches. One of the 2-wire cables goes to the other light fixtures. The other 2-wire cable goes to the garage.

Connect all grounds together and to each switch

Connect the white in the 3-wire cable (that has the hot black) to the whites in the two 2-wire cables.

Connect the red in the 3-wire (that has the hot black) to the single pole switch.

Connect the hot black to the black in one of the 2-wire cables.
Either the other light will come on or the garage lights/door will work.

After you have determined which 2-wire cable goes to the garage, connect the hot black (in the 3-wire cable) and the black to the garage together and add two pig tails.
Connect one pig tail to the single pole switch. Connect the other pig tail to the common of the 3-way switch.

Examine the other 3-way switch to see which wire is connected to the common screw. The common screw will be black or brass. Traveler screws will be silver. Connect that wire (at the top of the stairs) to the black of the other 2-wire cable going to the light fixture. The other wires in the 3-wire cable between the two 3-way switches should be connected the same.

Typically, the travelers in a set up like this would be red and white, leaving the black to be connect to the black going to the fixture.

Another way would be to see if power is at the common at the other end(Other 3 way), That would tell you if it is the "Hot end", or the "switched end".
The other switch would be opposite.
If this is 1 circuit, you should be able to connect the known hot to each of the wires and see which are your switch legs.
Also check the other 3 way and see what colors are on the travellers screws(silver), likely the same at the other end.
If you apply power to the wire that is on the common screw of the other 3 way, then that is the switched end, and the box you are working on would be the hot end and need constant power to the common terminal.
Good Luck.

YES!! Thank you soooooo very much!! To have somebody know how to fix a mess like this only in description is truly incredible! Watch out the 4-way with two 3 ways is next.. don't worry this time I won't take everything apart! Thanks again from CT..