2011 Ram 1500. 3 times the battery has died. Once less than 6 months old, dealer replaced. Once April last year, replaced from parts store. This week. battery was drained to 9v. Truck was driven the day before and the battery checked good. Cant' find any drain but the radio. Battery has been at 12.4v for the last 3 days. Thinking it may have been the fuel pump relay from all I read. Has anyone done the external relay mod or have any other ideas.