factory alarm disarm, 2000 explorer

Of corse I checked the wires, but I didn't really know what I was looking for. It says the wire is a neg. Just to update, I did get the problem fixed. Though there are two drk. GREEN/ purple wires in the kick, both of them read 0.00V. Voltage would pulse to .002V with factory lock or unlock, otherwise everything was 0.00V. After wiring the relay and disarm signal to both wires and even grounding both wires - still had no success, factory alarm would not disarm with remote start disarm/unlock. I went into the door and looked at the door lock - there are three wires that emerge from the connector and one is drk. GREEN/ purple. I tested it, resting 0.53V / 12V when armed. I wired this up to my remote start disarm wire (neg. 200mA pulse), and it WORKED. I don't know why this wire worked vs the two in the driver kick (identical wires). Maybe they went through the fuse panel or some other circuit. I just ran the disarm wire through the door and soldered it to the drk. GREEN/ purple wire in the door. Everything works perfect.