'93 Nissan Maxima Question???

Hey guys, I was just wondering if anyone knew of any electrical flaws with the Nissan Maxima models dating from'92-'94. For some reason, when I shut the car off the headlight(s) or highbeam(s) turn on and kill the battery (I've gone through 4 batteries already! - Thank God for warranties!). This car runs like a beast so I want to fix the problem and keep it alive b/c it still has A LOT of juice left in the tank. What should I do???

ps. I've put a brand new alternator in recently and it still has the same problems


thanks