One headlight (drivers side) comes on,randomly, on my 1996 Infiniti G20. Only way to get it to turn off is dri

can't turn it off unless i drive it around the block,then turn everything off. Anyone have any ideas? My mechanic says I have to bring it in when the light is on, but the garage is closed at n ight, and if the light is on all night my battery will be dead.Anyone had this problem?