2003 XLT No start, everything dead, anti-theft light solid red

[IIGood]

First, I'll precede this by stating that I replaced the battery in my '03 XLT this weekend. Did it mostly because the one that was in there was the wrong size so now I've got a DieHard Gold in there that is the proper size for this vehicle.

We've had snow yesterday and today so I've driven the truck yesterday and today with no issues.

Today I got home from work, shut the truck off, and everything died. The autolamps went out, power locks wouldn't work, nothing. I tried to crank it but absolutely nothing happened except for the airbag light on the dash dimly lighting. The anti-theft light on the dash went to solid red.

I figure I'm screwed. I went ahead and started clearing snow off my other car and by the time I finished that, the anti-theft light on the Explorer was back to it's normal blink. When I opened the door to get in, I heard clicking from under the dash, like morse code, and the light was blinking in sync with the clicking. I shut the door and tried starting the truck but again, nothing happened except for the airbag light. Then the theft light went back to solid red.

I know there have been numerous threads related to this issue but I can't find the one(s) that have this particular issue. I only have the one key so I can't try a second key to see if that'll start it.

Please help! I'd like to drive the truck tomorrow since the roads are still less than optimal for a Mustang GT to drive on!!

 

[IIGood]

...well...I just disconnected the battery for about 10 minutes and after reconnecting the cables, it fired right up as if nothing ever happened. W T F.

 

[Burnout]

I know it's a simple suggestion, but sometimes the simple things are the ones that get us:

You replaced the battery last weekend, it's possible when you put the cables on the new one in a way that was bumping them around. Consider you're driving home, they come loose (not fully disconnected or you'd definitely notice that), you turn your vehicle off and everything goes away. Your disconnecting and reconnecting may just have been a good way of inadvertently adjusting the cables. Others might have firsthand experience and be able to point out it's not that, but it's the first thing that comes to mind for me.