I have a 2002 F-250 7.3. When I keep it plugged in there are no problems but if I leave it unplugged and don't start it for 2 or 3 days the batteries drain. Through research one possibility popped up as a bad GEM module. That makes sense due to the fact that I also have no power locks, radio won't turn off when I open my door, no warning signal when I open door with keys in ignition, no reverse sensors and a couple other things. In order to replace the module do I need the exact same module number or can I buy any module that fits and just get it programmed. Or do I have a completely different problem