I have a friend that has a 2017 F150 King Ranch with a 3.5 echoboost. He is having a few problems that are hard to resolve. His horn does not work. His oil pressure guage goes to normal after engine start and a few seconds later it goes to zero and he gets the oil pressure warning. He has had the oil sensor replaced and no change. He has oil pressure and no timing chain rattle. Anyone have any ideas on what may be the cause?