Im not on here much these days, I work way too many hours, but I do have input for you. You are doing pretty good with your attempts at troubleshooting, but I think I see a mistake you are making.

Here is how I check that pin:

Start engine.
With top "closed" or "up", measure the voltage at that pin, it MUST be zero.
Now, turn the D handle and push the top away from the windshield frame.

You should now measure bias voltage, I can't remember what it is, I think it's 5 volts but it may be higher. This rise in voltage causes the PTCM to tell the BCM to lower the windows, but not two inches, it lowers them all the way down.
If you have no voltage, CUT THE WIRE about two inches from the connector. Does the pin now have voltage? If so, your issue is the switch or the wire is shorted to ground somewhere. If you have NO voltage with the wire cut, the PTCM is not generating bias voltage. This can be a bad PTCM, but PTCMs rarely fail. Verify good supply voltage at C1-pin 10, if you have good voltage here, I might concede the PTCM is bad.

Here is the thing:
1) If the windows do not go down when you turn that handle, you can FORGET: fluid levels,sync, the divider switch, the top open switch, the phase of the moon, and all the (bad) advice people are giving you. If the windows do not go down, the issue involves the PTCM, it's power, the wiring to that ONE switch and nothing else. Turning the D handle, with the engine running, MUST result in the windows going down.

2) If you are working on this without the engine running, you are wasting your time.