Motion detectors hooked into HW system no longer working.. ??

we have 3 Visonic Spy 4 motion detectors on our stairs that control 2 sets of lights. A few days ago, they quit working. (lights still work, but not via motion detector)

Checked (and rebooted) the power supply to the motion detectors. That didn't help.

The motion detector feed comes into a Lutron HWI-CCI-8 in the basement. That panel is daisy chained to a 4 series processor (and an 8 series, but I don't think that one comes into play here)

The green LED is on where the motion detector feed comes into the CCI.

When I pass under one of the SPY monitors, the motion detector feed at the CCI shows a voltage. (Interestingly, when I pass under the other two, it does not. Not sure if that's at all relevant. They all worked a few days ago)

green lights are on where the daisy chain feed (link 6) comes into the 4 series processor. BUS3 on the outlet shows a blinking green light (TX) but a solid orange one (RX). The orange light goes out when I disconnect the BUS.

I am ASSUMING the black and red wires from BUS 3 go to the 2 light switches that control the lights on the stairs (that should be activated by the motion detector). The light switches still turn on the lights when pushed, but there is no voltage at the black/red wires that connect to the purple/gray ones on either switch. There is a third switch next to those two that seems to control nothing but does show voltage when the grey/purple wires are each touched with the voltmeter.

Our Homeworks system is also connected to an ELAN system. That system indicates the lights come on when I walk under the motion detectors (even though they do not).

Feels like the motion detectors are fine, the processors are fine, but something (?) has failed between the series 4 processor and the switches (or both the switches failed.. which seems unlikely). Or -- that third switch somehow plays into this and it failed. Or some part of the circuit that it is on.

There were no storms/power outages in the timeframe I'm talking about.

the whole system was installed in 2009/2010.

Anybody have any suggestions for what else I could try or what the problem might be?

The CCI-8 acts as a keypad and is wired into the keypad link on the processor. This can be link 4, 5, or 6 of either processor.

Link 3 is a serial connection. That is probably how Elan is talking to the Lutron system. I would disconnect this link while troubleshooting.

My first thought is, the Series 4 processor can power a few keypads but typically has a plug-in power supply for keypads. It's not uncommon for the power supply to fail. The keypads may light up but they won't actually function. I would unplug any other keypads (on the processor the CCI-8 is connected to) and see if the system works. Any plug-in power supply will work just match the voltage and power tings of the exisiting one. Keypads are polarity sensitive so make sure you get the +/- correct.