My truck did the same thing a cpl years ago man, The fuse block shorted out ,the truck tried to start on its own at 4 am too ,it cost me a new fuse block,new starter, windshield,etc,etc, so THAT was cool . I had to take the Windshield out cause a new one was comming and in cleaning the sealing surfaces at the drivers side bottom corner theres a few spot welds that mate the fender rail to the firewall and when all the paint was off I saw that there was a crack at the spot weld. The water came in at that point and followed the harness right into the fuse block and over time just corroded it all inside. Ill try and find the pics for you,Good Luck Bro