Electrical issue

So up to this point, I've had no electrical issues with my XJ. But yesterday morning, when I cranked my Jeep to go to work, I noticed the battery seemed nearly dead. Then at work on my break, I tried to start it and it was dead. Charging system is working fine so I went to Walmart, they said the battery had no charge at all, and I went ahead and bought a new battery(because I'm stupid like that.) I cleaned all the corrosion off my positive cable, installed the new battery, cranked it up and notice that the parking lights and dash lights are on like that I had the headlight switch pulled out to the first click. Tried cycling the head light switch all the way out and in several times but they wouldn't turn off. Headlights came on and went off normally. Spent a while Googling it in the Walmart parking lot and when I couldn't find a solution, I decided to head home. Got in and put my foot on the brake and the dash lights went off. I got out and looked and sure enough the parking lights were off. Now they turn off and back on normally with the head light switch.

No amount of Googling has turned up any obvious answers.. At first I thought this was a headlight switch problem but after digging online, I'm really starting to wonder if I have some wires grounded out somewhere. Are the parking lights and brake lights connected some how?

I would check the grounds, I am not sure how many are in that circuit but I would guess there is at least one near the tail lights.

Electrical gremlins can make you crazy. I had an issue with my wife's old 97 S10 Blazer where the interior lights would randomly go on and off. It ends up it was the lumbar control switch in the driver seat, as you would move around in the seat the wires for the switch would ground out on the seat frame and since the interior lights and lumbar (possibly all of the power seat) were on the same fuse grounding the lumbar switch caused the lights to come on. I probably never would have tied the two together if I hadn't had noticed that I could make the lights come on by moving around in the seat.
Long story that has nothing to do with our issue I realize other than to say good luck. :D

I think this is probably the right approach. There may be a bad ground, or grounds somewhere and power needs someplace else to go. Start with engine to body and go from there. If that doesn't do it, you might need a new headlight and or brake switch

It's not doing anything now. I believe gremlin is an appropriate word. Guess I'll just let it slide until it sticks its head back out.

I still have nightmares about electrical problems with an 87 Chrysler Conquest TSi I used to have. But a for sale sign fixed the problem.