Hello Kevin, there is no reset button for this thermostat since it is ran by 2 ‘AA’ batteries. I would check your batteries and reinstall those and possibly uninstall and reinstall the unit, making sure your wires are going to the correct letter for your setup. The colored wires may represent something different for your setup. If you have the old thermostat you can refer back to it to see what the previous setup was before you changed it. Since the room temp is not moving on the thermostat when the A/C is on, there is a connection issue or set up issue (You can check your settings - press and hold the ‘Menu’ button for 5 seconds. You will need the guide to review each setting and to make sure they are correct for your home’s A/C unit.) The Quick Installation Guide has troubleshooting suggestions to try, but it seems like something is going on somewhere else in your cooling system. You can find the guide online www.honeywellstore.com/store/images/pdf/rth5160-honeywell-thermostat-manual.pdf