[papajam]

If I understand the symptoms, the battery goes flat after it rains, it sounds like the water is providing a path from battery positive to ground somewhere and draining the battery. But it's not a dead short. As John said, the burned amp wire may be a good place to start. I'd also check the junction block on the left inner fender and the wires to it for signs of chafed insulation. You might want to try hooking up an ammeter in series with the positive battery cable. Then, using some kind of sprayer (like a Windex bottle) filled with water, spray water around the length of the engine bay harnesses while looking at the meter. If (or when) the meter starts showing an amp draw, your getting real close to where the problem is.