Well, after about two and a half years, my GD00Z-4 has stopped working.
Everything behaves as expected (door position correctly indicated, flashing light and beeping for ten seconds, etc.), except the relay does not close.
I pulled the GD00Z-4 and its sensor from my garage, and put them on my bench. I removed my jumper wire, and connected the relay contacts (the “push button” contacts) to a 5 Vdc supply through a series resistor.
Then I watched the SS test point with my voltmeter. When the relay contacts were open (“button not pressed”) SS was close to 0V. When I “pressed the button” (shorted the relay contacts) SS was close to 2.5V. So that monitoring circuit seems to still be working.
Next I watched the relay contacts with my voltmeter. My meter was set to VDC with the MAX/MIN function enabled. The meter normally shows 5V. When I used SmartThings to activate the door, I expected the MIN value to go to near 0V; but, it did not change. So the relay did not close.
One side of the relay coil is connected to +12 Vdc. The other side of the coil goes to a pair of transistors to ground. I used a small resistor to jump around the transistors to ground, and the relay clicked. So the relay seems to be functional.
Next I watched the base/gate of the transistors with my voltmeter. It normally showed 0V. So when I used SmartThings to activate the door, I expected it to go to some positive value. It does not.
I traced that signal all the way back to the processor. How do I know it’s a processor? There is a “PIC ICSP” programming header right under it. The red arrow in the following photo shows the pin that should drive the relay, and you can see the programming header near the bottom.
I peeled off the label (no point in worrying about warranties now!), but the silkscreen on the part had been buffed off. In any case, that pin always stays low. It never tries to close the relay. So now I have an expensive door position sensor.
My adventures with the GD00Z-4 have come to an end. I will not buy another. I’ll find some other solution. In fact, I have already started down that path.
I was annoyed that I could not use Google Assistant to open/close the garage door, so I wrote my own SmartThings device handler and app to convert a Z-Wave relay into a door opener. All I have to do is get my own tilt sensor, and update the app to behave like the old garage door app. You can find that project here: https://github.com/mcavoya/garage-door-button
I hope Linear figures out why the GD00Z-4 has so many reliability issues. Best of luck to everyone still trying to make it work.