you ask someone if you can use their battery to charge yours with jump cables
Or... This may sound silly, but you can still use the key, like we all had to do in the old days......
Put the key in the door and turn.
If the battery goes dead flat the door will still unlock manually with the key.
By inserting the key in the door lock and turning.
By inserting the key in the door lock.
Unlock the door with your key.
By using your key to unlock the door.
Use your key to unlock the door.
Stick the key in the door lock and turn.
The battery in the remote may be dead, or the remote or security system may have a fault of some sort.
By inserting the key in the door lock and turning.
pretty sure you can use the valet key that is tucked up inside the key fob to unlock the door.
To unlock a 2016 Mustang when the battery is dead, use the physical key hidden inside the key fob. Press the release button on the fob to access the key, then insert it into the driver's door lock to unlock the door manually. If the fob's battery is weak, you can still use the key fob to start the car by holding it against the start button while pressing it.