Nest E Thermostat Connection

[Pinkb1883]

Can someone help me know where I should plug this blue wire?  Is it in Y or C? I only have 4 wires.  Blue, White, Green, and Red.   I plugged the blue on into Y1 like it was in the old thermostat setup however, the temperature was stuck at 32 degrees and had a low battery message preventing me from logging into the WiFi or turning the AC on. With this setup, all the tests worked, but temp didn’t adjust. My house was about 80 degrees and it said 32.  Help please. 

[David_K · Accepted solution]

The wire colour alone isn't enough for us to advise. Do you have a photo of your system wiring before you connected it to Nest Thermostat? Use a photo sharing service and share the link here if you can?