Before doing anything, why not look through the drawings you do have, and confirming the connections by, yeah, crawling up under the dash with a flashlight and tracing the wires?
While you're at it, maybe clean up the wire harness a bit, instead of leaving things like Dsubs and switches hanging freely in mid-air?
Yes, the Dsub is probably to the Dynon (I have one on my D10), but the switch could be anything...trim reversal, audio switch, who knows? The only way to really verify is to look...and THEN test the functionality that you think it's connected to.
FWIW, the D10/100/180 stuff hasn't had a software update since 2016...