Yellow Button

use your multimeter and test continuity. It may branch off giving you a couple different 'beeps', but it will narrow it down. One of the gurus will read this soon and pipe up. Im still thinking they bump the starter. Have you tried it with the key 'on'? and out of gear if a manual...

It's an automatic. I'll spend some time chasing with a multimeter and see if I can trace it.

Yeah, wasn't sure what it would do (Wile-E-Coyote ejection seat or something) so I progressed through key positions and then idling.. Nadda.

Appreciate you putting some thought to it. There's also something that looks like a round, red light about 1" in diameter on the side of the dash, driver's side. Not sure if it's related.

A mystery.