Steve, I could go on and on about what your problem is most likely caused
by, but I dont have the time.. LOL I will say this. Your generic electronic
module (gem) controls 2 relays in the central junction box (cjb for short,
aka fuse panel). It is called a cjb cause now its not just a fuse box
anymore. Anyway, the relays are your batt saver relay and interior lamp
relay (ILR). When you open a door (any one of them) the GEM will ground the
control side of the ILR and close the relay. This will cause the courtesy
lights to come on. The problem with the CJB's and GEM's in your vehicle is
that they plug directly into each other. There have been known cases of
water intrusion into the CJB/GEM's on these vehicles. Either way, its more
likely the GEM than the CJB, but you are looking at some good money to get
this fixed.. I would suggest you let the dealer work on this one..

Ford Tech