Resposta para "Where can I purchase parts for the nest 2nd generation thermostat?"Thanks everybody, I have similar issue and after a long troubleshooting I found the Y terminal (A/C compressor in my house) was always on, even if my Nest (2nd generation) is off. The heater (W) and fan (G) works fine, and the Nest was working for several years without issue. I read that it could be a faulty C wiring so I add a another wire to reinforce the C (common) signal just in case, but nothing change, the Y is always on even if I remove the face-plate. I was looking to replace the (I think) faulty backplate-2.7 when I stumble into this forum. Now I now that I have to replace the thermostat (which of course will be another brand, it’s not cheap to replace it every 3 years!).