Check page 170 of the 2017 F150 owner's manual. There has to be a slot for the key in case the batteries in the FOB are completely dead, because in that case the vehicle will not recognize that the FOB is present.
Interesting. You got me thinking. I left the FOB in the house and unlocked the door using the emergency key. Get a notification in the dash to start the truck or the alarm will sound. Push button would not start the truck. Alarm sounded. Had to run in and grab the FOB to turn the alarm off.
Looks like there has to be a way to use the key to start the car.
Hoping someone finds out how.
---------- Post added at 08:14 PM ---------- Previous post was at 08:03 PM ----------
Found this video. Not about the F150, but our trucks likely work the same way.
Maybe when the FOB is in the slot below the cup holder, even with a dead battery, the truck will start? Looks that way in the video. Maybe take the batteries out of the FOB, put it in the slot and see if the truck starts?
https://www.youtube.com/watch?v=3ur1qsePu3E