Did it do the same thing whether auto or manual? This sounds like a different type of issue, usually the auto headlight feature just affects that only.

 

Yes. Remove the plastic kick panel trim that's on the passenger side between the fuse box and the door jamb. Behind there you will likely find the ground terminal or the sheet metal it's supposed to be screwed to is rusted away.

Clean off a spot a few inches up and reattach the ground wires there and you should be good to go.

 

I had this same problem with my new to me 2005 Lariat. One time the auto lights started working. I realized that grandkids had been in the backseat jumping around. After a few days they quit working. So I turned the auto lights on, got in the back seat and started flailing about. I hit the left rear seat back with my elbow and shazam, they started working again. I don't use them, because there is obviously a bad connection, but it did prove the problem is in the BCM. It's such a pain to remove the back seat I haven't looked to see what a repair may entail.

 

You only have to fight the back seat one time, then you can modify it to come out with ease.

Even then it's really not that difficult. A little patience, of which I have none, it comes off.

You can then permanently fix the problem. I never use the automatic headlights, just because there's lots of trees around and even during the day, they pop on and off.