What could be causing the battery to drown out over night on a 2002 Dodge Dakota Sport?

There is a way Zach. Get a multi-meter, you don't have to disconnect the battery and (easier with a helper) and set it to 12V DC and put the red wire on the +positive terminal and ground the black, wire. See what amperage shows.Begin to pull fuses, one by one until the amperage drops below 0.5amps (normal maximum draw for a parked, non-running engine--should be less but with a security system/alarm etc. it might draw that much) and there is your culprit. Unless you simply need a new battery, if yours is 3 to 5 years old.

check the battery if the level is low than 12.5 volts it needs charged. jump the vehicle and then test the battery if it is indicating 13 or 14 then it is charging. So it is not the alternator, so then it could be the battery is bad. If the battery is not bad then you need to check for a parasitic draw. How to resolve a parasitic draw can be viewed at the following. http://www.youtube.com/watch?v=zdIKNnwEjIs

Had a similar problem with my 1990 Dak. Turned out being a bad starter even though the starter wasn't 'yet' exhibiting problems.