This hasn’t happened yet, but a friend of mine just bought a 2007 Lincoln Town Car and asked me about this because I work at auto auctions in my semi retirement, and am supposed to be an “expert” on this kind of stuff. Haven’t a clue on this one and the owner’s manual doesn’t address it.
Opening doors is all electronic, no outside insert for a key. Doors can be opened many ways…key fob numerical code on door etc…but no mechanical way to overide it except door handle on inside. Do have ignition and trunk keys.
Friend asked me …OK battery is dead as a doornail (left lights on or something). All doors are locked. How do you get in the car?
Maybe there is some kind of chip or something that will allow the electronics to work with a dead battery?
Would just remove the neg terminal of the battery and see what happens, but friend doesn’t want me to do that.
I’m sure Lincoln wouldn’t have such a potentially dangerous thing (suppose a kid was inside?)