What's this plug for?

[Copasetic]

Going over my Dad's 2000 XJ while mounting a winch for him and came across this plug that I can't find anywhere to hook it back up to:

It's on the passenger side fender well right behind the battery. Any ideas?

 

[ABadJeeper]

Did you check to see if it goes to the sensor in the battery tray. I think it is supposed to shut things down if the battery gets over a certain temperature or something. Could be something else all together too.

 

[RenegadeT]

good guess ^^^, I'll take a look at my '99.
Only other thing I can think of would be fog lights.

 

[Bullardbs]

They also have a cooling fan resistor in that area too for the electric fans looks like that plug too