My 1995 Chevy S-10 Blazer's radio was equipped for AM stereo.
Of course, by then, most AM stations were sports or talk format,
so even on the few that broadcast a stereo signal, all that
really came over in stereo was some of the commercials. Still,
all AM stations sounded much better with the "AM Stereo" switch
on. There was much more high-end in the audio, so in addition
to killing the stereo signal, turning off the AM stereo switch
also added a very effective low-pass audio filter.
No car I've owned since has had an AM radio that sounded as
good as that one, although the best AM radio I ever heard was
in my 1965 Ford Galaxie 500 hardtop coupe. (I owned it in
the early 80s when music was still a feature of the AM dial.)
People thought I had an FM converter hidden somewhere.
David Breneman [log in to unmask]