Where is the thermostat located in a 1999 Cadillac deville?

In a 1999 Cadillac DeVille, the thermostat is typically located in the engine compartment, specifically at the engine's coolant outlet housing. To access it, you generally need to remove the upper radiator hose, as the thermostat is situated beneath it. It's a good idea to consult the vehicle's service manual for detailed instructions and diagrams.