how to test a factory disarm wire?

Turn key in drivers door to unlock....wire will show ground. Turn key back to lock or center position, ground goes away.

As stated turn the key in the drivers door to the unlock position and the wire should read a ground, turn it back and the ground goes away. If your using a test light, close all the doors and arm the factory alarm. You mentioned the key fobs don't work with the driver door open hit the lock switch once or twice and close the door the alarm should arm up. (Watch the icon on the cluster) Reach in and open the door which sets off the factory alarm. Hit the suspect wire with your test light and it should disarm. I would suggest method one as poking around at the BCM with a test light isn't always the best idea. For your vehicle light green (-) is correct at the BCM or it might be easier to grab it in the drivers door jamb boot or where the door boot harness comes into the car. Good luck, Mike