ztarum

Yes. It wasn’t completely separated though, just cracked open about 1/3 of the way around. Looks to have been over tightened to the bulkhead which put some undue stress on the cover breaking the seal. That said, the box has a vent/drain hole anyway so the breached seal probably wasn’t a factor. I’m wondering if anyone has a pin diagram for the plug? I should probably test grounds and supply power in case the fried board was a symptom of some other fault.

I think I found the issue. The board inside the 3E Black Box has a burnt area.

Yes, it sure seems to. I didn't test everything while I had it out, but I definitely used it to turn the seat heaters on. It also seemed to navigate between screens fine and all the touch features worked except the speed setting adjustment.

I plan to dig in tonight and check all of the wiring. No apparent battery issues at this point (good voltage, engine cranked strong, etc.), but I'll try a swap if I can't find anything else.