Sometimes when a digital thermostatis not operating properly this will.

Changed batteries in honeywell thermostat now not working. Connecting r to y will turn on the condenser (outside) unit (assuming everything else is working okay). This honeywell model has a thermometer which measures the room temperature and helps in maintaining the temperature of the room. In the backward position, you have to keep the batteries for some time.

Let's check to make sure you didn't damage the stat then. After keeping he batteries in the backward position for 5 seconds, remove them from the chamber. Open the side compartment in the thermostat to reveal its batteries.

The a/c still did not work, but. Just insert some fresh batteries to fix the problem. One possible reason for this could be that you haven’t put the batteries correctly.

Check the power the first step will be. Press the down arrow button until reset appears on the screen. If “my ac is not working” means that it is blowing hot air after the batteries have been changed, check whether the thermostat setting is on “cool” and not on “heat.” it is possible that.

Put the new batteries in the compartment and slide the protective plate over them. Turn off your honeywell thermostat and unplug it from the wall. You can try removing the batteries and installing them backwards for 10 seconds, then putting them back in correctly.

If your thermostat screen is blank, the first step is to check the batteries in the device. Press the cloud icon and hold it. Before this, you could attempt to.