Well, while I have the connectors unplugged at the SJB and the door switch, I decided to go ahead and test the grey/red to make sure that it wasn't still grounded, and it is. I thought it may be a bad connector at the door switch, so I cut the wire about 5 inches from the door switch connector and tested the wire again, and it is still grounded. So, I pulled the connector apart at the SJB to see if there might be some corrosion inside, and it was clean. So, I cut the wire about 4 inches from the SJB connector and tested from pin 3 to ground, and no beep from my multimeter. Yay! So it is the gray/red wire grounded somewhere from the passenger door switch to the SJB. So sometime in the near future, I will just run a new wire, but for now, I'll just leave it cut at the SJB connector so at least my door ajar light and dome light will go off and everything will still work properly from the drivers side door.

 

Maybe this will give you some ideas (for my 96 Ranger XLT):
https://www.ranger-forums.com/genera...-alarm-141760/

Also shows dome light switch inserted in door latch if I'm not mistaken.