Some relay is sticking on.
If on wet, snowy, salty days if I don't turn off my climate control switch fan switch sometimes when I return to my 1997 Expedition the darn fans, front and rear, are both running with the key pulled. Most of the time on high speed...bad relay or short. Doesn't do that when dry. Get the volt meter out and go circuit hunting.
Additionally it is far easier to 'get voltage out of a battery then to put it in'. Clean tight good wire connections to the battery?