Door lock/arm circuit

I'm in the process of hooking up a remote starter, hoping for some info on the lock/arm system. I have a 97 Jetta Trek. I see there are 2 12V wires and 2 other wires that I think come from the door lock unit. The 2 others seem to give a neg pulse when the door is locked/unlocked (one for a lock, the other for an unlock). Grounding these wires does nothing though. I assume the arm signal must get sent from the central locking unit. I don't have any wiring diags other than the Haynes manual ones, though.

Can anyone offer any advice??

Thanks in advance
Paul