Grand Cherokee Auto Unlock

Everyone that I know that owns a Grand Cherokee with the auto-lock after ignition and drive wants the doors to unlock automatically upon key removal.  Specific information on the door locks and relay would be appreciated.  I also own a 99 cherokee that doesn't have auto-lock, or auto unlock, like my wife's '97 Grand Cherokee, and I want to also add that feature to my Jeep.  

So I guess my question is the type of door locks used in Jeeps, ie. positive vs. negative, and where should I start looking for relays etc.  I have a basic knowledge of electronics, enough to do damage but not enough to have it "click right away". Please help!!!

a databuse wire controls the lock, unlock, factory alarm, and domelite, located at the test connector under the dash, and you need a module to interface with it. therefore im not really sure if you can do what you want to do.

Both year jeeps use a 5 wire reverse polarity system through a multiplex module.

1999 Jeep GC: Use ORANGE / black and pink/black at the drivers door lock switch to lock and unlock the drivers door.  Use ORANGE / purple and pink/purple at the passengers door lock switch to lock and unlock all of the other doors.  

1997 Jeep GC: Use ORANGE / purple for lock and pink/black for unlock at the drivers door switch to operate the drivers door lock.   Use BLACK/ white for lock and pink/black for unlock at the passenger front door switch to unlock all passenger doors.  It is required to interface in each door even if the vehicle is equiped with keyless entry.