2003 Chevrolet Venture electrical problem

First my running lights came on while the key were out of the van and the doors closed. The battery is being drained. Then it would ding like the keys were in the ignition and the door was open but the keys would be out and the door closed. Then the power locks keep trying to lock themselves while driving a lot. This has been going on for a while. I have replaced the battery twice and I keep unhooking the battery cable from the fuse box when I go somewhere. Also the starter stay engaged sometimes when I let go of the key when starting. I took the fuses out for the lights and the door locks but still have battery drainage and I have replaced the fuse box due to the stud breaking off the fuse box from constantly hooking and unhooking the battery cable. Please Help. Anything that might be the problem would be greatly appreciated. I will make a donation if you can find the solution to my problem.