Thanks for your reply. I know I had a lot of info in my first post, but I did already test the motor itself and it is fine. The real problem is a break in the wire that comes from the underhood fuse panel (fuse 30) to pin C of the resistor pack in the cabin down near the blower.
Everything works fine if I run a test jumper wire between those 2 points. Just looking for the best way to find the break in the wire and ultimately repair it. Maybe my only option is to run a new piece of wire (correct gauge) in parallel to the factory harness from the fuse panel to the resistor pack connector.