Ford Super Duty (1999-2016) :: F350 - Randomly Clicking Relays And Battery Running Down

Bottom-line question: is there a way to tell if a GEM is fried?

'99 F350 with a known water leak (not where it leaks, but for sure that it does--glove box, floor mats, etc.).

Recently started running the battery down, and then noticed that under low-voltage conditions it would click the door-lock relay back and forth, etc.

Now, after several inches more rain, it's making clicking and other electrical havoc noises any time it's not running, key in or out, even when the battery is up enough to start the truck (V10). I charged the truck and started it, drove it around to let it charge some more, and when I got home and shut it off, it was clicking as bad as ever.

After reading on the forums a while, I went ahead and pulled the fuse panel and GEM. The two big fuse panel connectors were definitely wet inside, and there's a little corrosion on one or two of the bayonet connectors. The GEM itself doesn't seem wet, and it doesn't look/smell like I've let the smoke out of it.

What do I do at this point? Last time, after I charged it up, it seemed to hold a charge and didn't do any clicking. I thought at the time it was related to the door switches that had been on the fritz (and which I lubricated after reading about where they are). Now, I suspect it was just because it had been long enough since it was rained on that things had dried out.