I have this odd issue with two Insteon on/off switches that are in the same box and side by side, but operate two different lights. They are two-way switches (that is, on/off for a single light and not in a 3-way circuit).

If I turn on Switch A, it turns (its light) on fine. If I turn on Switch B (next to Switch A), it turns (its light) on fine, BUT Switch A turns off. I can then turn on Switch A, but if I turn off Switch B, both Switch B AND Switch A turn off.

I wired a lot of my Insteon switches, but I think electricians wired these.

Could this be a wiring issue? An IoX issue? Where do I start (wiring or IoX), and if it is an IoX issue, how do I debug this?

There's 2 starting diagnostic paths, I'd start with the easiest

• Factory rest and restore each individually. Test again. This is relatively easy to try.

  The writeup makes it sound like they've been in there a while, and I can't imagine how wiring would cause that.. I suppose it's possible.... But- if it didn't do it before and started now, a wiring problem seems unlikely. I've had Insteon switches installed for years and sometimes they "lose it" and need to be reprogrammed. Little is lost if this path is wrong

• If that didn't do it, turn on the event viewer level 3, and do recreates to an ordered script (what you wrote above) so it can be compared to the event viewer results. Post it back here

If both of those yield nothing, then its time to dig them out of the wall

Edited December 29, 2025Dec 29 by paulbates

To rule out IoX (your controller), just unplug the PLM temporarily and redo your tests. If things stay the same, then it's not a program.

1 hour ago, ctviggen1 said:

If I turn on Switch A, it turns (its light) on fine. If I turn on Switch B (next to Switch A), it turns (its light) on fine, BUT Switch A turns off. I can then turn on Switch A, but if I turn off Switch B, both Switch B AND Switch A turn off.

I think @paulbates is right that the switches need to be reset. Look up the proper way to reset the switch in the Insteon "manual". What you're describing sound like a direct link has been made for "Switch B" to control "A". Might be odd that B doesn't turn both on, but turns both off. Since the link isn't in the IoX system, but direct connection with the devices resetting them should work. I would remove the devices from IoX, factory reset them, then add them back to IoX. When you add them back to IoX be sure to select the option to remove existing links (even though you factory reset them this is an additional step that the IoX should attempt to remove any links i the device as it adds it to IoX.

If that doesn't work then could be a wiring situation.

A question pops up in the back of my mind: is it even possible to program (link) a switch send an Off command to another switch when turning it On?

Sorry for my delay -- had to work and then had a holiday. I'll try removing them from IoX, then factory reset, then adding them back.

What happens to programs though? Will they come back into the programs I have once I re-add them, or do I need to somehow figure out in which program they are currently in, and re-add them to the programs?

This is a box with 4 switches that turn on various lights in the front of the house. They have been there a while and I don't remember how I programmed them, although I do think I had electricians install them (and maybe they programmed them?). I did many installations, but this is one I did not do.

By the way, what does the "device links table" tell me in the admin console? I ran this for both switches. There are a bunch of hexadecimal numbers, but both have 3 of the 4 hexadecimal numbers of the other in one entry. That is, Switch A has 28.85.7E of 28.85.7E.1 that is Switch B's address. Is this meaningful or meaningless?

On 12/29/2025 at 11:16 AM, Guy Lavoie said:

A question pops up in the back of my mind: is it even possible to program (link) a switch send an Off command to another switch when turning it On?

Yes. "ON" levels can be set to zero. That is, when a controller device is telling a responder device to turn ON, and the responder's ON level is zero, the result is that the responder device turns off when the controller device sends an ON command.

1 hour ago, ctviggen1 said:

What happens to programs though? Will they come back into the programs I have once I re-add them, or do I need to somehow figure out in which program they are currently in, and re-add them to the programs?

I believe, unfortunately, the latter. I believe the process of removing them from EISY removes them from programs. Hopefully, I am wrong.

If you have a spare switch of the same type, add it as a new switch with a temporary name. Then bring up one switch you want to rewrite to, right click and select "replace with" and assign it the spare switch. This will adjust your programs automatically. Similarly, add back the original switch as a spare, and "replace" the temporary switch back with the original one, again getting your programs automatically adjusted.

But before all that, have you tried "restore device" on the switches?

Edited Thursday at 05:11 PM3 days by Guy Lavoie

55 minutes ago, oberkc said:

I believe, unfortunately, the latter. I believe the process of removing them from EISY removes them from programs. Hopefully, I am wrong.

All good advice but I’m curious as switches can be programmed at switch without eISY. Is it possible that happened?

If you ever find out, you might win the Nobel Insteon prize!

3 hours ago, hart2hart said:

Is it possible that happened?

They can be "linked" without the ISY, but "programs" are part of the EISY. It is possible that a device had pre-existing links? Yes. Is it possible that a device had a pre-existing program? No.

The process of adding a device to the EISY can remove existing links (an option that one must choose when doing so). Alternatively, factory resetting a device before adding to the EISY would remove existing links.

11 hours ago, ctviggen1 said:

Sorry for my delay -- had to work and then had a holiday. I'll try removing them from IoX, then factory reset, then adding them back.

What happens to programs though? Will they come back into the programs I have once I re-add them, or do I need to somehow figure out in which program they are currently in, and re-add them to the programs?

This is a box with 4 switches that turn on various lights in the front of the house. They have been there a while and I don't remember how I programmed them, although I do think I had electricians install them (and maybe they programmed them?). I did many installations, but this is one I did not do.

I personally would recommend against removing them from IoX. At least at first. Personally, I would stop all IoX programs. I have a program to do that, but if you do not unplugging the PLM would work quick as well. Then turn your switches on and off and stuff. If problem is gone, it is an IoX program. If problem is not gone, do not remove them from IoX. T (Too much unnecessary work and you loose lots of fun troubleshooting options).

Next I would compare device links. Alt click on one of the switches in Admin Console>Diagnostics>Show Device Links Table. Window pops up and IoX queries the link table stored in switch. When done, click on compare. If everything is not identical, that is probably your issue. Restore devices in the alt click menu of the device.

If all that does not work, then I would factory reset the devices and see if the problem still persist. If it happens after factory reset you have bigger issues.

And yes, you can absolutely program Insteon switches locally. I had an entire Insteon system that was completely locally programmed at the devices pre-ISY. It was horrible.

On 1/1/2026 at 7:27 AM, ctviggen1 said:

What happens to programs though? Will they come back into the programs I have once I re-add them, or do I need to somehow figure out in which program they are currently in, and re-add them to the programs?

If you haven't removed and reset yet this part gets a little tricky. It might, but might not have any impact on programs.

I would suggest the following two steps if you haven't removed them yet:

• Make a text copy of ALL programs

  • On the programs tab right click on the root "my programs" folder. Select the last item of "Copy Folder to Clipboard"

  • Paste all programs into a text editor (i.e. Notepad on Windows)

  • https://wiki.universal-devices.com/ISY-99i/ISY-26_INSTEON:Tree_View
    

• On the Programs tab you can (again) right click on the root folder and use the "Find/Replace" option.

  • You can then search by device and make note of each program that device is referenced.

  • https://wiki.universal-devices.com/ISY-99i/ISY-26_INSTEON:Tree_View#Find/Replace

Sometimes when you remove items and add them back exactly as you have them they might not mess up programs. Just don't do anything in IoX while you're doing this process. Don't close Admin Console, don't click on a different tab, just remove the device from Admin Console, Factory Reset it (at the switch), Link in Admin Console. Use the exact same name for the device. It could be that it will re-populate in the programs, but having the text copy and knowing what programs it is referenced in will help a TON by being able to go back and repair any broken programs.

There is no way to backup the programs then re-import them so having a text copy of ALL programs is key to try to fix if stuff does go into a broken state of missing device in programs.