I’ve replaced the fuse panel under the dash in the passenger side as it was shot, brand new part from Ford. I had to get the keys reprogrammed so I could start the truck, all appeared to working. I installed a new alternator as well, and it was only charging about 6V back to the battery. Replaced that other big fuse and am now getting proper voltage back from the alternator to the battery. Truck is not running fine and starts but the interior lights are flashing on and off. I am at a loss and don’t know where to begin. Any help is appreciated guys thanks.

 

Don't know specifically for F150s but I know for Expeditions if the BCM(interior fuse box) is not programmed exactly as per workshop manual the interior lights flash to indicate this.