I went searching for the alarm this weekend. To my ear, I think it's behind the speedometer display. I removed a lot of dash panels, but never got there. The sun shield panel over the speedometer has 2 screws. I removed those, but then was faced with what else was holding the panel. Pull, pry and break some clip...... I decided against that and gave up.
I'll bet the alarm is part of the instrument cluster panel. Once I find it, I'll put duck tape over it to lessen the noise.
If anyone out there bought the service manual, can you look at what's holding that panel in the place.