Anyone solved this problem before, or can walk me through how to decide which wire connects to which using a multimeter?

Mirror has never worked so decided to dig into it. Of course I had cut off the connector before I realized that wiring diagram did not match reality.
Wiring from loom matches diagram. Wiring from motor of mirror does not.

And as far as testing, I see the black wire running to ground. That mean the mirror has to be bolted to the door to work?

Thanks!