If your vehicle has keyless ignition and the battery dies in your key fob you will need an alternative way to get inside and start your vehicle.
2015 ford fusion key fob dead.
After inserting the key fob use the start stop ignition button and brake pedal to start your vehicle as usual.
And again the key fob can be removed from the backup slot once the vehicle is started if you wish.
To remove the cap insert the key blade into the slot on the bottom of the handle right image bottom arrow and press up.
How to unlock and start a ford fusion with the hidden lock cylinder when battery in vehicle of fob are dead.
New in the 2015 mustang the 2017 fusion and as seen above the 2018 expedition the backup slot is hidden under one of the cup.
The 2015 mustang and the 2016 edge have since been added to this list.