I have a 2003 4.7L. At random times the left front headlight turns on while the car is turned off and the light switch is turned to off. I just noticed it this afternoon and I now find that it was on long enough to kill my battery. An ideas on how this could happen? Is the headlight switch bad? Thanks

 

sounds like a short to me, time to get the multi-meter out and start probing for shorts on that wire.

also check the relay that controls the headlights

 

Grab a switch from the junkyard. They're pretty easy to find... Durango or Dakota.

 

It's just ONE headlight? Hmmm, possible CTM. You could try slapping it and see what happens.