I have a 2003 F150 SCREW with a 5.4 engine.
Recently the battery drains if the truck sits for 2-5 days.

I took the vehicle to the nearest Dealer to be worked on. The dealer has been working on this issue for over one month( off and on, twice we have been to the dealer to pick the truck up, only to find that the truck would no start).
the last time the dealer/service Mgr. said the engine computer and the GEM were not communicating properly.

does this sound correct?
the GEM was replaced by the dealer and we went to pick the truck up and the battery was DEAD!

does anyone have any ideas or suggestions for a fix to this???

 

Go get the truck.
They are not showing any competency.
.
Check the alternator for shorted diode stack. Easy to do. Disconnect the heavy lead form the alternator terminal. Be very careful and touch it back on the terminal with the motor off. If it sparks the alternator is the problem.
In some cases the alternator case will be warm long after the motor has cooled.
If this does not prove out, fix up a small size 12 volt lamp in series with the battery lead of a size bulb that will light enough to see the drain then remove fuses one at a time until the lamp goes out or very dim.
Finding the cause is relatively easy, the fix can be more involved once you see what the cause it.
Good luck.

 

the dealer said the radio was making the draw on the battery.

The radio was replaced and we will find out if they are correct THIS TIME.