03-09-2026 12:42 PM
I have a 5 wire system. Brown White Red Green Blue. How do I wire the nest with these colors?
03-09-2026 12:51 PM
E103 error Y wire issue
03-09-2026 10:04 PM - edited 03-09-2026 10:48 PM
@Andy53 ,
In the installation instructions you were advised to take a screenshot of you old thermostat wiring before you removed the old thermostat. Looking at that screenshot, you should see letters next to the terminal connections. just match the colors and let her from the old one to the color wire to the new one.
AC Cooling Wizard
03-09-2026 10:52 PM
@Andy53 ,
If your thermostat is reporting an E103 on Y1, it is seeing excessive voltage coming in the wire. This sometimes happens when put the R wire in Y1.
Double check the wires from your old thermostat screenshot and make sure the color of the wire attached to Y on your old thermostat.
The Cooling Wizard