Auto on headlights not always working

SOURCE: Headlights won't turn on. Daytime running lights stay on.

See if you can hold on your highbeams, as a temporary solution, until you can check and see if the fuse in the switch to turn your lights on is burnt out. I had the same problem with my car and apparently it was a defective part that GM had produced, but obviously they won't replace it free of charge. I would suggest going to an auto-wreckers and picking up a new switch there... the part usually costs around $400 in Canada.

SOURCE: headlights and dash light dont work

You would have to check and see if you are getting any power out of the light switch. There is a seperate wire for the headlights and the dash lights.

SOURCE: ford expedition yr'00 headlight not working checked fuses..

The low beam headlamps have a seperate fuse for each lamp in the central or underdash fuse panel.
The right headlamp is fuse fuse 26 (10amp) and the left is fuse 28 (10 amp). These fuse are hot only when headlamps are on so you need to test them with a test light with headlamps on. If they do not have power to them then concern is either headlamp switch or daytime running lamp relay if your vehicle is equipped with this feature, or a bad multifunction switch.
Power leaves the headlamp switch on the RD/YE wire and goes to multifunction switch. It leaves multifunction switch on the other RD/YE wire The wire will then go thru either a connector c2003 located behind the passenger side air bag behind the dash or to the DRL relay if your vehicle has this feature and leaves there on RD/BK wire to the headlights .

SOURCE: Blows fuses when parking lights are turned on. Headlights work fine even running lights.

If it only happens when you turn the switchto the parking lights then it is most likely the swich that is the problem. Light swich failure appears to be a common fault with fords

SOURCE: Automatic headlights not comming on

Bad connection to the light sensor which will no doubt be mounted on top of your dash?