Ford recalls 874,000 F-150, Super Duty pickups over fire risks
The problem stems from the engine block heater.

Engine block heaters are useful in cold climates, providing a little extra heat when it's needed. They are not, however, supposed to provide enough heat to start a fire.
Ford on Friday issued a recall for approximately 874,000 examples of the 2015-2019 F-150 and 2017-2019 Super Duty pickup trucks . Roughly half of the recalled trucks are located in the US, with the rest in Canada.
All of the trucks involved in the recall are equipped with engine block heaters, which is the root cause of the issue at hand. Contaminants could work their way into the cable's splice connector, including water, which could corrode and harm the cable over time. If it's corroded enough, it could cause a short that might trip household breakers or start a fire.
Ford says it's aware of three fires starting at the engine block heater, and one incident also included minor property damage. Thankfully, it has not learned of any injuries stemming from the problem. Ford says the safety risk is only present when the vehicle is parked and the block heater cable is plugged in, so those truly worried about the block heater should avoid plugging it in.
Since the problematic part is just a cable, the fix is relatively straightforward. Dealers will inspect all recalled cables, and if it's damaged or corroded, they'll replace it. If it's not damaged or corroded, dealers will apply dielectric grease and reattach the cable. If replacement parts aren't available at the time, Ford will notify owners once they're available.