I tried to lock my Model X and it failed to lock with the key fob. I assumed the fob battery might be dead so I tried the other fob and determined it was a dead battery. I then followed the instructions in the O&M manual to hold the fob with the dead battery near to bottom of the door post on the drivers side to see if I could unlock. No luck. I tried numerous positions and it would not unlock. I am now worried that if I am not carrying my cell phone with me and my fob goes dead I will not be able to get into the locked car. Many times I do not carry my cell phone or leave it in the car. Has anyone had luck with unlocking the car with a dead fob battery?