My third (upper) brake light is inop. My regular brake lights work as do my turn signals and parking lights.
Yes I did check the bulb and it is good. Checked it with my other Fiero.

First one with the correct answer gets a------------

It wires directly to the brake switch on the peddle.
Check the wire there and see if it's knocked off or broke.

I will check that when I get home from work tonight. Thanks.

Any other things to check??

If you have a meter you might check the socket to see if one side has a good ground. If you don't find a ground in the socket that could also be your problem. I have no idea where they would have grounded the light.