2001 Oldsmobile Aurora location of an air compressor

There is part, which I believe to be an air compressor, in my car that needs to be replaced, but I'll be darned if I can't find the part on any auto parts website, and it is in such bad condition that I don't want to risk pulling it and taking it to Auto Zone. It'll probably fall apart if I even try. It's located in the front left wheel well, just in front of the horn. If I could name the part when I call parts shops, it'll help a lot. Any help you can give would be appreciated.