Drivers side rear door says its open.

The switch is built into the lock / latch assembly. Unplug the four-pin connector from it. If the light goes out, replace the assembly.

In that wiring harness, ground the terminal for the tan / yellow wire. I can't tell from the wiring diagram whether that switch opens or closes when the latch is closed. The only way to know for sure is to take the right door apart and make a comparison. Instead, if grounding that wire makes the light turn off, suspect the latch. If there's no change, that wire could be grounded to the body, or it could be broken between the door hinges. You said you checked it for continuity, but also check it for being shorted to ground.