Unusual Add-On Switch Behavior

I have a three way switch in my family room that I had wired with a motion sensor switch and an add-on switch and everything worked well. After a few months my add-on switch stopped working, but my primary switch was fine.

When i opened the add-on box, i saw that the neutral wire pigtail had fallen out of the bundle. I reattached the neutral, and while I had the power off, iI also swapped the motion sensor switch with a motion sensor dimmer switch.

When I turned the power on, the motion sensor dimmer worked perfectly. The add-on switch I noticed was now only able to turn the lights on, not off. However, the add-on is able to dim and turn off the light if the light is switched to 68% or less! Basically if the light is under 68%, the add on switch operates perfectly (dim up/down, on/off). Above 68%, it can turn on, not off.

Any thoughts on compatibility or a broken switch?

Brand and model almost certainly matter. Does the documentation with your add-on list it as compatible with the dimmer you’re now using?

So far I’ve done my 3-ways using Zooz Zen26 and Zen27 switches/dimmers. They work with the existing dumb secondary switch. Saves a lot of hassle.

1 Like

HalD points to a rather important consideration: Some switches that allow 3-way configurations (eg: GE) do not work with an existing 3-way switch. The Traveler connection is marked “Not for AC line voltage”.
Others (eg: Zooz) are designed to work with an existing 3-way switch (and consequently allow full line voltage to be connected to the traveler).
So, check that your add-on is both compatible with the motion-sensor switch and with the way it is currently (no pun intended) wired.


Sorry all - i found my stupid error - the add-on neutral was pigtailed to a line/load connection of an adjacent switch instea.