That's what I would start with..

 

Do I just take out the 4 screws and pop off the cover to change the bulb??

Yes, that's about all.

The bulb is a 921.

There is a gasket between the lens and housing that you might find to be compressed or distorted beyond reusing. It's best to replace it. The gasket part number is 81572-0C050 and costs about $7.00

 

I took off the lens and pulled the bulb out and put back in and now it works. I figure there was corrosion in the socket that was scraped off when the bulb was taken out/put in. The gasket seems fine.

BUT--there are clips that I pushed in thinking thats how the whole unit comes out. Now I cant get the clips to pop back out. KRAP. I put the lens back on with the 4 screws and everything seems tight, but I dont know if something is loose because of the clips.

 

I didn't notice that you have a 2002 (1st-gen) Tundra until you mentioned clips I and saw your truck info in your profile.

Maybe someone with 1st-gen knowledge can step up here.

Good Luck.

 

UPDATE: The problem was the metal contacts that hold the bulb in were loose, so I took tweezers and pinched them closer and now the bulb fits tight and is on