some guys leave the old wheels/tires in the garage or near where they park & it resets over night, it goes on after about an hr. of driving or after driving a certain # of miles.
how about just popping out the fuse and see if it works. my light has been on for a few months and is driving me nuts. I know all 5 of my tires are at 35psi.
http://www.flickr.com/photos/36613889@N05/4855862258/