Should My Thermostats Panel Operate On The 2 Aa Backup Batteries Or Be Hardwired To Common And Have Batteries As Backup When Power Is Out?
Panel Lights Up With Batteries In, Does Not Without Batteries. Don't Know Where Common Wire Originates From. Can I Splice Into One Of The Other Wires, G, Y, W To Connect To C Terminal?

Thanks.

Batteries are used as a backup to not lose settings when power is off. The stat should have a common wire. It is usually blue and in you case connected to C terminal