Yes
To replace the thermostat on a 1999 Chevrolet Lumina, first, ensure the engine is cool and disconnect the battery. Drain the coolant from the radiator, then remove the upper radiator hose connected to the thermostat housing. Unbolt the thermostat housing to access the thermostat, replace it with a new one, and reassemble by reversing the steps. Finally, refill the coolant and check for leaks.
driver side engine in the middle od both heads. fallow the top rad hose back.
It is located in the transmission.
Replace
Some where between the grill and raideator
The alternator blocks access to it. You need to remove the serpentine belt, then the alternator to get to the thermostat.
Follow the upper radiator hose to the engine block. The part the hose is connected to is the thermostat housing. The thermostat is under it.
It is on the top of the steering colum. It is a small black button.
It is mounted on top and inside the fuel tank.
Did you try changing the bulb? It might be burned out.
It is in the front of the engine, to the right of the thermostat housing.