I have a '96 2500 turbo diesel 4x4 that we just purchased last fall. Since purchase no problems until this last couple of weeks when the truck, after sitting for a couple of days, the batteries go dead. I still have full "sound" and lights but the battery gage reads "8". We have jumped the batteries, bringing the meter back up to "14" but within a couple of hours it loses halve it's charge just sitting there. We're thinking that perhaps it's as easy as needed new batteries, and if so, how do we change out the duel batteries, and could it possibly be something else that we not familar with, it being diesel and all? Any help would be appreciated.