How do you replace thermostat on 2003 ford Thunderbird?

To replace the thermostat on a 2003 Ford Thunderbird, first, disconnect the negative battery cable and allow the engine to cool. Drain the coolant from the radiator, then remove the upper radiator hose connected to the thermostat housing. Unbolt the thermostat housing, replace the old thermostat with a new one (ensuring the gasket is in place), reassemble the housing, and reconnect the hose. Finally, refill the cooling system with coolant and reconnect the battery.