[89ltd]

you will need a test light, disconect the positive battery terminal. Connect one side of the test light to the battery positive post and the other to the positive cable from the van. The light should not come on if there isn't a problem, maybe a vary slight dim is okay, from things like the clock. In your case I'm sure it will light up. Now go to the fuse box and unplug one fuse at a time until you pull the fuse that makes the test light turn off. At least this way you can find the item thats causing the problem. ( don't say you don't have a 12 volt test light as they are about $3)