This may be a dumb question
I have a Carrier Air Conditioner and the display shut off
I took off the thermostat cover and there appear to be 2 small cylinder batteries but you can't remove them
Does the power come from them, and if not... how do I fix?

The batteries are for backup should you lose power, which is what I suspect has happened.The furnace has the transformer in it for the control voltage , start there, if it is a newer furnace check for a bad fuse on the printed circuit board or if it is an older furnace check for 24 volts at the transformer. Good luck, Mike

The display on the digital thermostat is what keeps all of the settings in memory when the unit is off... the AAA batteries will come out of the stat... make shure that you have replacement batteries when you change them out... be careful to install the new ones in the same direction + -... I am going to guess that all of your settings will be lost without the display... you will need to reprogram the stat... instructions are often found on the inside of the cover that you took off to find the batteries.:)