Fuse 7 also powers the BCM (Body Control Module). The BCM controls most of the body related systems (headlights, auto headlights, vehicle theft, rke, interior lights, etc). This is the most likely cause of the problem. Its located on drivers side of instrument panel (dash) below the farthest left switch pod. You'll have to remove a panel or two below steering column to get to it. Unplug the connectors to it (3 of them, I think) and leave it unplugged for a couple of days and see if the battery still drains. The optional power amp is also powered by fuse 7. That should be under the rear seat, possibly rt side. But start with BCM, thats usually the one to cause problems.
93 Grand Wagoneer (de-wooded) 5.2 Mag, 2"BB, Magnaflo Cat, Gibson ex, K&N CAI, Mopar pcm, 32" BFG AT, Accel truck ignition