2003 Ford Explorer Dead Battery

There may be a parasitic draw on the battery. Check the draw on the battery, should be less than 30 milliamps. IF it is above that pull a fuse one at a time to naroow down the circuit that is the drawing circuit. Once you establish the circuit first check the obvious like a switch that is on.

Are you haveing any problem with the domw light staying on? The fords are notorious for the latches getting sticky and leaving the ciruit active to the dome light. Light lube soak will usually fix that.