Yup, sounds like it got power sometime when it was wet...
I recently had the same thing.. I got caught in a severe thunder/hail storm, 20 miles from home with my top, but no windows or doors. So my back seat is apart and drying (I never did get around to painting my personal box.. go figure...) but the wood suprisingly didn't get wet. And the amp is also still drying... I will put it back together this weekend. It's been about 2 weeks...
Everyone knows my system so, let's just say.. I had 6" of standing water in the rig (and this happened twice in the same week, second time I left the windows down to try to dry it out when a rainstorm hit and the runoff of the garage went RIGHT in the window... Enough water it was pooring out the door seams...)
Anyhow, the key to surviving this problem is just time.. the longer you let it dry out, the more likely it will work ok. Also opening it and removing any mildew or surface corrosion is also key.