It's low on the heater box, behind the glove box area, if I remember right! There may or may not be a small cover over it, too.

Here's a link to a picture of it:

http://c2c.activant.com/ctoc/index.jsp?ID=bEz1sGyk_BU50LyZ_CUdGM2RDUF86ZTEKUnIf