Got this hunk of junk in for inop turn signal and ABS light on so first thing I checked was turn signal stalk, flasher relay, and hazard fuse. Unfortunately I jumped the gun and threw in a new turn signal stalk and that did not fix the problem. Checked relay (videos showing bad solder) and looked a-okay.
Poked around the underdash fusebox and found the ABS and reverse light fuse blown, replaced the fuse and the turn signals work but the reverse lights came on while it was still in park. A few moments later the reverse lights went off as the fuse blew again (as I was shifting the lever.)
Looked through wiring diagrams and this particular fuse (RUN A22 - FUSE 12 10A) feeds the reverse light, ABS, and turn signal relay.
The turn signal works and the ABS light went off with key on and new fuse so that's ruled out.
My attention is now the reverse lamp circuit. It's a 10amp POS feed to the trans range sensor/reverse switch (not sure) then to the rear lamps.
Another odd thing I've discovered is the gear selector display shows all gears selected when in park.
Trying to narrow down this issue because changing the range switch involves dropping the valve body in these trans so I need to make the right call before tearing into the trans.