Dead Battery & Headlight Issue
 

I have a 97 Camry XLE with about 160k miles and i parked it in the driveway today for about 6 hours and when I went to drive it the battery was completely dead. The headlight switch was on, but it's almost always on because they shut off when the car is turned off anyways so I usually just leave it on. When I went to jump start the battery it was trying to turn over but never did, and the headlights came on, even though I had turned the switch off. I took the battery out, since it is about -10 degrees right now, and put it on a trickle charge overnight. Anybody have any ideas what may have caused the battery to go dead? There were no internals on, doors open, etc. I have no stereo equipment hooked up or security system. Any ideas why the headlights would come on while being jumped even though the switch was turned off? Any help would be greatly appreciated.

RE: Dead Battery & Headlight Issue
 

How old is the battery, when a battery fails it can do so quickly. Cold temps hasten battery failure.

The headlights may just be resetting themselves would not worry about unless they fail to turn off on auto setting. Suppose it is possible the headlights failed to turn off and ran down the battery.

Have the battery load tested, turn the headlights off when not in use. If using the same battery carry jumpers as it may be dying.