I have installed an alarm/remote start in my 2005 Prius. (Before anybody asks why, => 118 degrees!!) My chosen alarm does not integrate with the factory fob, so I have to contrive a method. Essentially, I am going to listen for a lock/unlock command and use a couple of relays to trigger an imbeded spare remote for the alarm. The alarm is wired to the lock and unlock wires as the smartkey is locked out when the car is running. If I gathered my signals there, I would end up with a feedback loop. What I need to do is find wires that carry a lock/unlock command from the door handles (smartkey), after the key has been confirmed by the car, but before it is sent to the door locks. I do have the repair manual and the wiring diagram, but it's making my head spin trying to figure out what I want. Anybody care to take a stab at it? If you have any questions, or need clarification, just let me know.
On my 07 door switches come to the blocks under the drivers kick. http://www.selidori.com/tech/prius/DOC/Tech2006/Wiring%20Diagrams.pdf 2006 wiring. Start at about page 201. At the top of the "book" are the block numbers and locations. Example shows IE1 (block), next to it is 13 or 14 pins on the block which are for my key lock/unlock from the door. Your predicament is interesting.
krg03, I've been going over the diagrams trying to figure out how to make this work. I think I have an idea. If I can get a signal from the lock sense wire, I can use it to with some relays to have the buried fob arm only when the car is unlocked and disarm when it is locked. I think I will get a double lock and unlock that way, but I can live with that. P.S. Do you have any details about the AutoUnlock proximity mod mentioned in your signature?