[tjhnson]

I replaced a chandelier with a new one, and wired it exactly as it was before... but it will not turn off. I have a three-way switch (two switches, one light), and it's on a dimmer.

When installing, I thought it may have fried dimmer, so I replaced the dimmer... same thing.

In the switch box (dimmer), I have:

Two black wires from the wall threaded together (one is hot)
Two white wires from the wall threaded together (neutral)
Green ground wire
Red wire.

I've connected green to green, black to black and red to red.

I tested the wires with a circuit tester, and I have juice when testing ground to the black wires and ground to the red wire... but no juice testing black to red.

The other switch in the three-way switch is now behind built-in bookcases. Before tearing those out of the wall, I want to troubleshoot and make sure I really need to, but I'm stumped. Help would be appreciated

[ballengerb1]

Open this Installing A 3-way Switch With Wiring Diagrams - The Home Improvement Web Directory and scroll down a page to 3-4 options for wiring. One of your switches could be bad or the way you wired it.

[tjhnson]

I have the first diagram, fixture controlled by two switches with power through a switch box. I just disconnected the red wires at the switch and nothing happened... light remained on.

[hkstroud]

I've connected green to green, black to black and red to red.

Does that mean that you connected the green of the dimmer switch to the ground, the black of the dimmer switch to the black of the house and the red of the dimmer switch to the red of the house wiring?

If so, you do not have a 3-way dimmer switch. The dimmer must be a 3-way to work with the other 3-way switch. It will have 3 terminals or leads in addition to the ground.

[ballengerb1]

If you removed the reds now flip the switch, did the light go out?

[tjhnson]

Disconnecting the reds changes nothing. Light stays on, will not turn off.

[ballengerb1]

?? Even when you flip the switch? Put test leads on the switch screw with the black wire, other lead to a neutral or known ground. Do you get 120 volts off that screw no matter which way you flip the switch?

[tjhnson]

HKStroud... yes, that is how I wired it... however, there is an additional wire on the dimmer switch... it's red with a white stripe. The dimmer is able to act as a three way switch OR a single pole switch. I have simply capped the red/white wire. However, I've also tried connecting the red/white wire instead of the red wire, and connecting BOTH red and red/white to red. No difference.

[tjhnson]

??? even when you flip the switch? Put test leads on the switch screw with the black wire, other lead to a neutral or known ground. Do you get 120 volts off that screw no matter which way you flip the switch?

Don't have a switch screw, just black wire coming out of switch, but yes, I get 120v with the switch flipped both ways.

[ballengerb1]

You have a bad switch which must be replaced. The screws I am talking about are the screws that attach the wires to the side of your switch, there are at least 3 and usually a forth green screw.

[tjhnson]

No screws on this dimmer... looks like it's directly wired directly into the switch internally.
This is a new dimmer switch... bought it on Sunday to replace the old dimmer switch, because I suspected the old one was bad... but the new one does the same thing. I tend to agree with your diagnosis, but if this switch is also bad, there's something in the wiring that's causing the switches to blow out. I don't want to connect another one until I can figure out what is causing that.

Would it be a good idea to install a standard on-off switch to test? Would that tell us anything?

[ballengerb1]

No screws on the side, then it must be done with short pigtails coming off the dimmer with wire nuts, still should be 3. It could be the other switch that is bad, the one at the other end of the room, there are 2 switches, right? You could test with a standard 3 way switch but it could be either of the 2 switches that's bad.

[tjhnson]

Thanks... that other switch being bad is what I'm thinking - and was afraid of. It means I have to take out a section of built in bookcases... thanks much for your help!

[hkstroud]

Connect the white of the 2-wire cable to the white of the 3-wire cable. Connect the black of the 2-wire cable to the common of the switch (should be the black wire of the switch). Connect the red of the switch to the red of the 3-wire cable. Connect to the red with white strip of the switch to the black of the 3-wire cable. You won't blow switch by miss wiring.

If you want to check other 3-way switch, check it at the dimmer switch box.

If the 2-wire cable is the power coming in you should have voltage between the black of the 2-wire and the ground. If you do not have voltage the power is coming to the other switch. In this case the 2-wire cable is going to the light.

In either case if you connect the black of the 2-wire to the black of the 3-wire cable, the light should burn with the switch in one position and go off when the switch is moved to the other position. Connect the black of the 2-wire to the red of the 3-wire cable and the light should burn when the switch position is reversed.

If power is coming to the other 3-way switch you should have voltage between the black of the 3-wire cable and ground when the switch is in one position. You should have voltage between the red and ground when the switch is in the other position.

It does not matter if the 2-wire cable is the power coming in or if it is the cable going to the light. The black of the 2-wire cable goes to the common of the switch. The other two wires of the switch connect to the red and black of the 3-wire cable.