One headlight working


Oct 23, 2009
In my gf 2000 mustang the drivers side headlight is out. The passenger side works fine. I replaced the bulb and it didnt help. Both headlights come on when i hit the high beams.

Any ideas,
Very frustrated
  • Sponsors (?)

Check the plug connector to the headlamp bulb. I had one that was bad. Sometimes the light woud mysteriously go out and I had to realy mess with the plug to make it come back on. After I replaced the plug, problem solved. Bad connection on pin where it plugs into bulb caused only HB to work. And if you broke the plastic tabs off, that can cause the plug to come loose easily. When you unplug, never pry up on the tabs. Thats what breaks them.
Check headlight fuses

For the 1999-2004 MY, there are separate fuses for the left and right low beams. There is also a time delay circuit breaker in the head light switch.

Going to assume that the headlight connector is good and the grounds are good.

Fuses schedule [Battery Juncton box (BJB F1)], [Central Junction Box (CJB F2)]:
F2.4(10a) Right low beam
F2.10(10a) Left low beam
F1.2(30a) All head lamps
F2.38(10a) DRL

Pull the fuses and inspect them. Sometimes it can be hard to see if blown from the top.

Do you have after market head lights? Some draw way more power than stock units. This can lead to blown fuses and melted connectors/wires.