Need help, Chevy Express dead after deep puddle

[kschwies]

Hoping to get some help in the next couple hours, we have a 2012 Chevy Express 3500 with Quigley 4X4 conversion.  We had to drive through a huge mudhole last weekend (long story), and at one point wound up briefly pushing a bow wave over the top of the van.  Water flooded the passenger compartment, but to my surprise the van kept chugging along and out the other side.  We then drove home 1.5 hours at highway speed with no issues, but I did notice I was getting an airbag warning light.  We left all the doors open to let the van dry out, next morning van was completely dead, as though  no battery was hooked up.  I put a charger on it overnight, battery is now fully charged, no change.  Any ideas here?  I'm headed out of town and my wife needs this van to take the family to our cabin this weekend!  I doubt it's a quick fix but I'm hoping someone can give me some insight.  Thanks in advance.

-Kurt

[kschwies]

Checked the battery terminals, they look brand new.  No corrosion.

[silveradosid]

does the dash light up with the key on