My auto lights have been troublesome and I've noticed it ever since the temperature has been below freezing. I generally keep the lights in the auto position and don't give them much thought, but a little over a week ago I noticed in the morning that they were not turning on. I flipped the switch all the way to the on position and they worked fine. There have been plenty of times in between now and then that they have come on just fine in the auto position and turned off with the truck off. There have also been times they turned on properly but when I turn my truck off the lights would not turn off. It's like they have a mind of their own so I have been just operating them manually. I've found it makes no difference weather the fog lights are on or off. I've noticed if they do come on like they should, I've never had them turn off at random.The harness is properly plugged into the light switch, I haven't pulled the back seat out to check out the rest of the harness, it's just odd to me that sometimes it works and other times it doesn't. Truck info is in my signature.

 

recalled this from a few months back, similar symptoms with autolamps.

https://www.f150online.com/forums/el...t-problem.html

Turned out to be burnt pins at the BSM ( Body Security Module ) behind the rear seat. Member even took some nice pictures of the BSM connector.

There is a thread in the Technical Article section on how to remove the rear seat, to gain access to the BSM.

I would start with this ( even though it is a hour or 2 of work ) first, rather then the std pull and test the headlamp switch, due to how close the symptoms appear on the surface to match.