courtesy lights
 

I have a 2000 expedition and have a courtesy light issue. They come on intermitnetly while driving or parked, running or not. I tried to spray down the latches on the truck and thought that it took care of it. Started doing it again recently. The alternator went out recently could this be one of those built ins that tell techs the battery is getting bad? Anything else I should take a look at?
Thanks