I found out where it goes. Open your rad cap and just drop it in. I hope this helps someone else.
Annette
Follow the upper raditor hose from the raditor to the motor, the raditor hose is connected to the thermostat housing, take the houseing off, the thermostat is under the housing.
The 2002 Frontier thermostat is located in the thermostat housing. The housing is the connection for the top radiator hose.
The thermostat housing is located at the end of the cylinder head and behind the timing belt inner cover.
The thermostat is located in the housing where the top radiator hose connects to the engine. You will have to disconnect the hose and unbolt the housing to get to the thermostat.
Follow the upper radiator hose the the engine. The thermostat is located under the housing at the end of the hose.
Most thermostats are located in the thermostat housing which is at the lower end of the large top radiator hose.
The thermostat housing is located at the engine end of the lower radiator hose.
The termostat in the 3.1l is located in a housing in the lower intake manifold. The upper rad hose is conected to the thermostat housing.
inside the bell housing
the thermostat is located under the thermostat housing on the front of the motor where the top rad hose connects to.
The 1999 Pontiac Bonneville thermostat is located on the front of the engine, near the bottom. You can follow the top radiator hose from the radiator to the thermostat housing.
Assuming you have the 2.2, 4 cylinder engine, the thermostat is located on the side of the engine that faces the firewall.