OnOffLedMode=Single on VZM31-SN can cause burn-in

I was (somewhat stupidly, as it turns out) running Parameter 259 (One Led Mode in the Inovelli docs, OnOffLedMode in zigbee2mqtt, not sure what it is called in other platforms) set to 1 for a while (probably nearly 6 months now?).

The only real usage of the light strip on that switch was to light up green at 100% intensity while the switch was on, for about 15-20 minutes a day (it’s running the vent fan in the shower). To be maximally generous, maybe 100 total hours of being turned on. I finally realized that the OnOffLedMode setting was why I was having trouble running notifications on the light bar, so I disabled that, and now it’s pretty visible that the green led in the bottom-most RGB LED has changed color over time.

It’s a bit hard to take a good picture of, but here are two that should make it easy enough to tell what im talking about.

If you are running OnOffLedMode set to single right now, I’d probably recommend not setting it to 100% intensity (oops, I should know better). For now I’ve swapped it to instead light LEDs 2-7 to the same color as before in the hopes of eventually evening out the wear across the other LEDs.

Could you try pulling the air gap and watching the boot sequence for LED 1? Does it have a visible difference? If not, I would factory resetting the switch (should be easy to reimplement) and see if the LED1 goes back to normal.

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Are you saying that you had it set for 100% intensity while the switch was OFF?

While I understand the logic there, you might want to reconsider. Keep in mind that the leds only have 3 real colors: Red, Green, and Blue. Those three colors are blended in various intensities to make all the other colors. For example to make purple, the Red and Blue elements are lit and mix to give the appearance of purple.

If you “burn-in” all your greens so they don’t look green anymore, then it will affect many other colors that use green as part of their mix. Personally I would leave the other 2-7 as is. I do see the difference, but I think I prefer the rest of the led bar colors to stay true and just have that one bottom one a little bit color shifted. But you might prefer to have them all the same, even if the color is shifted. Something to think about :thinking:

I’d be inclined to do a full reset here. The difference is pretty significant looking at the 2nd picture. I feel like this may be an issue with the original setting maybe sticking and mixing with the new setting (possible firmware bug?). If there really was “burn in” to the LED’s, you wouldn’t be able to install a new switch beside an older one without a noticeable difference, and I’m sure there’d be tons of reports on this already.

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I had a similar issue on one of my switches. The bottom color on the LED didn’t match the others, but it wasn’t due to burn-in. It was always there and the boot up sequence displayed all the colors correctly. A firmware update and factory reset cured it.


Thanks for the suggestions everyone, especially the tip to try the air-gap switch to see if it reproduces there. It doesn’t, so I guess this is probably a firmware issue somehow. I’ll try a factory reset today and see if that clears it up :crossed_fingers:

Edit update: factory reset seems to have fixed this, I guess it was just some weird firmware bug :person_shrugging: