You’ll need to remove the faceplate of your old thermostat to get at the low-voltage wiring and backplate ... If your system already has a C-wire, you can skip this step. If it doesn’t, you might need ...

However, it's important to note there isn't a standard color for wire colors, so be extremely careful handling any of them. Example of line voltage setup for the thermostat.GearBrain If you decide to ...