Nissan Repair: 1993 Nissan Pathfinder -electrical-, nissan pathfinder, battery terminals

Question
My Nissan, when driving with the lights on, starts to bog down and want to die.  The time display on my radio turns off.  When I turn the lights off the time display reappears and the car doesn't bog down, but does when going up hill.  I had my alternator checked twice by two different stores and it passed.  I changed my battery terminals.  Car ran okay for a while then a month later started doing the same thing.  Now I don't know what to do.  Should I just go ahead and replace the alternator or is it possibly a relay or ground proble?

Answer
John,

I have not seen a headlight switch do this before.  But, there is always a first time.  If Autozone or Checker inspected the charging system I would go back one more time and have them check it with the headlights off and then switch them on and see what happens to the state of charge.  Email me back with what you find.