This happened to me once. You will need to take it to a dealership the sensor is gone. I don't know the name of the sensor but it maybe on a recall. But mine would not start either, so eventually I had to put the truck in neutral and then start it keeping my foot on the excelerator and then pop into drive. Be careful when doing this it may jerk. And the truck did cut off at intersections so I had to keep my distant for the vehicle in front of me. And do the same thing until I got to the dealership. I ended up paying about $110.00 for them to repalce it. It has worked fine eversince.
You can find the 1999 Ford Expedition headlight fuses in the fuse box. The headlight fuse will be the numbers three fuse.
iin the manual that came with your expedition
Check Fuses Check Fuses.
where is the fuses for the factory amp in a 1998 ford expedition
Check fuses
Check the headlight switch and make sure you are getting current out of the switch when you turn on the lights.
Check your fuses.
Owner's manual.
check fuses
See if you are getting power to it - if so bad motorIf not check switch and/or resistor
Check Fuses
Check fuses