Auto Parts: pontiac aztek 2001, pontiac aztek, headlamp assemblies

Question
What is the proper name of part locaqted under the chasis that looks like an air deflector? It is about 3-4 feet long. I'm trying to locate a replacement for this.
Thank you

Answer
    Are we talking about the piece beneath the bumper?  That is frequently referred to as a valance panel or, sometimes, an air dam.  Anything further back would probably be referred to as a splash guard.  Some cars, like the Firebird, which lacks a grill, have a piece down there that is actually called an air deflector.   If you are calling salvage yards, just tell them what you told me, but be a bit more specific about the location of the part.  After all, it's the parts guy's job to figure out what you want.  How are you supposed to know that the rear window is referred to as the "backlight," or that the panel to which the headlamp assemblies are mounted is known as the "headlight door."  The panel to which the radiator is mounted is known as the "core support," because, in the old days, the radiator core was attached directly to the car and served as a structural member.  There are lots of examples of this, so don't worry about sounding dumb to the parts guy, he's used to it.