Mercury Sable Headlight Not Working

Hi, I Have Had This Problem For A While. When Dircing At Night, Everyonce In A While My Headlights Will Go Out On Me. The First Time, I Went...

Low Beams Dont Work But All Other Lights Do I Have Checked All Fuses Relays And Switches Everything Checks Out Great Cant Figure This Out.

1997 Mercury Sable - Low Beams Do Not Work, High Beams Do. Seems Turn Signal Switch Was Intermittent Before Lights Stopped Working....