How do you fix a blank thermostat?

Fixing a blank thermostat involves performing a series of simple diagnostic and repair steps starting with power restoration. First, if your thermostat uses removable batteries, open the compartment and replace them with fresh alkaline batteries. Second, if the unit is hardwired without backup batteries, check your home's main electrical panel to ensure the dedicated HVAC circuit breaker hasn't tripped, and reset it if necessary. Third, turn off power at the breaker, remove the indoor furnace service panel, and inspect the control board for a blown low-voltage 3-amp or 5-amp fuse, replacing it if the internal wire is charred or broken. Fourth, remove the thermostat faceplate and ensure all colored wires are securely clamped into their respective terminal blocks. You can verify that your fix was successful when the thermostat screen powers back on and illuminates.