A lady installed your Lutron 3 Way Dimmer (D-603P-IV) in her hallway single light fixture circuit that also has a regular 3 way (non-rheostat) switch at the other end of the hallway. Problem: When she pushes the knob on the 3-way dimmer it will not turn off the light; however, the rheostat (dimming function) will work. What is your best guess as to possible solution here?

You probably had a fan/light fixture there. One set of wires (probably coming from the dimmer) would be for the light. The other set of wires (probably coming from the switch) would be for the fan. With the power off, temporarily hook up two lamps, one to each set of wires. Then turn on the power and see which switch controls which wires. It is possible that one set of wires is passing through to another light fixture - in that case, that wire will be dead. Good luck!

They're right, you don't want to control the whole thing with a single incandescent dimmer. First of all, the fan-speed and the lights will all be controlled by the same dimmer setting (dim low, low fan-speed - dim high, high fan-speed) - and the dimmer's not rated to control fans anyway which can result in exactly what they said.

There is a Skylark control, the S2-LFSQ- where half the knob controls the light, the other half controls the fan. The only problem you may (and most likely) have is that in order for that to work, between the electrical box for the dimmer and the fan, there needs to be seaparate wire run for the fan, and a separate wire run for the light so that the dimmer can individual control both.

If that's a problem, I recommend the MA-LFQM-, which includes a module that you install in the ceiling with the fan. The wall switch it comes with speaks to that module, and gives you independent control of the fan and light without having to install new wiring. I have one of those myself, I've installed one in one of my friend's houses, and they work pretty well and then you don't have to worry about what wires you've got in your wall.

I don't think you can do what you are trying. The fan & light are on one circuit. Probably, originally, there was only a light fixture there. The fan/light is on a single circuit and the remote does the controlling of both units.
Now, you are trying to install a fan control and light dimmer but you don't have wiring for each separately.
You might be able to use one of the dimmer controls to adjust the output to the fan/light combination, but you can't control them individually, if I understand your wiring.
Gary

You posted under Leviton rotary dimmer.
Lutron and Leviton have many 3-way dimmer styles, and both make 3-way rotary dimmers.

I remember years ago replacing 3-way switches with dimmers and having same experience as you. One dimmer has to be ON for the other dimmer to dim.

Later I learned when you replace both 3-way switches with dimmers, you buy a control-and-companion dimmer set. One dimmer is main, and it lets you dim from both locations. The two dimmers communicate with each other electronically. Buy these dimmers at lighting store that specializes in fixtures and dimmers. Ask for most experienced salesperson.

I checked to see if rotary dimmers are made in the companion set. And neither Leviton or Lutron show 3-way companion set rotary dimmers.

1) Leviton spec sheet on rotary 3-way dimmers does not show companion dimmer. This indicates that Leviton rotary dimmers don't have capability of communicating with each other.

2) Lutron has image of 3-way rotary dimmers.
Image shows single rotary dimmer in 3-way & 4-way circuit.
This tells me that Lutron does not have companion dimmer for 3-way rotary dimmer.

The switch has gon bad on you. You need to replace the dimmer switch

The dimmer is worn out

Wall switches and dimmers don't come apart for repairs >> nobody sells parts >> and the wiring didn't suddenly go bad.

Sadly, yes, it just sounds like the switch got stuck. You should be able to yank that knob off and try to manually unlatch it with something thin and long (like a pencil) - just, do me a favor, and make sure whatever you use isn't conductive, there shouldn't be any exposed electrically, but just be safe about it.

If that doesn't work, call their tech support center at 1-800-523-9466 - they will most likely replace it for you.

This is a 3-way switch, made to control a light fixture that is also controlled by another switch in a different location. A typical example is a ceiling light fixture installed in an upstairs hallway, which could be controlled by switches at both top and bottom of the staircase.

The green wire in your switch is the ground connection, and joins to the green insulated or bare copper ground wire in the switch box. The red wire is the common connection. It connects either to the incoming AC hot wire from the electric panel, or to the hot terminal of the light fixture, depending on the switch location. The two black wires are traveller connections. They connect to the traveller terminals of the other 3-way switch.

If you purchased this switch as a replacement for a regular single-pole toggle switch or dimmer switch - one that controls a light from a single location only - then this isn't what you need and you can't use it. You'll know if you have a single-pole switch because it will have only three wires or screw connections. Return it and get a single-pole.

To install this as a replacement for a 3-way toggle switch or dimmer, connect the red wire to the wire going to the common terminal of the original switch. This will be a black- or brass-colored screw on a toggle switch, or the different-colored (not green, that's ground) wire on a dimmer. The black wires connect to the wires that go to the traveller screws (copper-colored) on a toggle switch, or the same-colored wires on a dimmer. It doesn't matter which traveller wire connects to which.

Note that if you're using a 3-way dimmer, only one of the switches can be a dimmer. The other switch has to be a plain old 3-way toggle.

The short blew the Lutron. Replace it.

You have to have a special ballast on the light to dim fluorescent light fixtures. You also have to have a special dimmer.