Weird Electrical issue after battery replacement!

I changed my battery in my 2012 CX9 after it went dead. It started fine, so I parked it and it sat for 3 days. I went to crank it and move it today so that I could mow the grass, and noticed that I had several warning lights on. TCS off, Oil light, Brake light, traction control light all on, and BCM light flashing. So I moved the car, cut the grass, came back a couple hours later cranked it, (all lights still on) and moved it back into place. I was getting no codes. So I disconnected the negative battery cable, and went to change an EGR sensor on my truck. Came back about an hour later, hooked the battery back, cranked it up, all of the warning lights are still on. Took it for a drive, about 3 or 4 miles, no change. Has anyone else had this issue? What was your fix?
 
I have experienced this when the battery is nearly dead. However, others have seen the "Christmas tree" dash when either the alternator voltage is low, or when the body control module is going bad.

Since the battery is new, it should be putting out 12V. You can check this, and assuming it's good, move on to checking the voltage when the car is running to verify the alternator is not failing. You should see close to 14V at the battery. If that's ok, I'd check the BCM. Do you have a sunroof? Sometimes the sunroof drain plugs up and water ends up running down the Driver side A pillar and right into the BCM...
 
The BCM makes a lot of sense. I do have a sunroof, and I had seen some water in the floorboard when I first changed the battery. I cleaned out the drain and dried that up, but never imagined a problem with the BCM. Thanks I’ll try that.
 
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