I am trying to install a motion sensor switch on a 3-way switch in my laundry room. both 3-way switches function normally if I use them now. One 3 way switch, we will call it #1, is by itself. It has 4 wires, the live black wire, red traveler, white traveler and ground. No other cable coming in or out. The switch has the black on the common (darker) screw, with red above it and the white by itself on the other side. There is always power despite switch position at the red and black wire.

The other 3-way switch, we will call it #2, also has a fan switch located with it in that box. Multiple cables coming in and out. The 3-way switch has same configuration with a black wire in the common (darker) screw and white and red in same locations. With a working 3-way switch on there, power switches between the red and white depending on both switch positions. It seems like the power TO THE LIGHT is the black screw on the common (darker) screw because light will not turn on unless power is running through that wire on switch #2.

I put the motion sensor in the switch #1 position, with black as the load wire, red and white as travelers and ground. When the motion sensor is installed, it is a 3 pole motion sensor switch, it will not work consistently. The motion sensor switch will click on and off, but it will only work depending on the position of switch #2. It seems all messed up...

  • do you want the motion sensor to turn the lights on if they would otherwise be off, or to turn the lights off if they would otherwise be on? Why not replace the three-way switches with permanently on connections and just rely on the motion sensor? Dec 8, 2013 at 10:42
  • Thats an idea, thank you. I assume I would put the motion sensor at switch #1 since that is where the hot is. Would/could I just cap off the other switch in the wall behind the plate to make it always on? which wires then would be connected to each other?
    – DIY tim
    Dec 8, 2013 at 16:09

1 Answer 1


Depending on the device you're installing, the installation can be a bit different. Consult the installation guide that came with the device, to determine the proper wiring.

I've randomly selected installation guides from a couple available devices, and I'll show the differences. Keep in mind that your device may vary, and you should consult the documentation with your device.


The Lutron installation guide, shows this wiring diagram.

Lutron wiring diagram

Which seems very straight forward.

  • Connect the Black (common) wire to the Black (common) wire from the device.
  • Connect the Red (traveler) wire to the Blue (traveler) wire from the device.
  • Connect the White (traveler) wire to the Black (traveler) wire from the device.


The Leviton Installation Guide, shows a bit more complicated diagram.

Leviton 3-way Wiring

They even provide a troubleshooting section, to help you get the thing working correctly.

Leviton Troubleshooting Guide

This is just a small sample of the available devices, consult the documentation that came with the specific device you are trying to install for proper installation instructions.

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