My problem with the same symptoms was a short/misconnection in the heated mirrors that were on 24/7 and killed the battery every night.Switch showed the mirrors were OFF but there was still current flowing.
Hard to diagnose heated mirrors in Arizona and Mexico but that was what it was traced to. 2007 Ford F-53 chassis. If possible get a DC amp meter- hard to find but available and find the wire with current( amperage) and disconnect -then find out what does not work. Took me several months to find it. Good Luck
