Usually, when one headlight is dimmer than the others, it is a loss of ground that is the culprit. Check for loose or corroded connections. If all else fails, a new ground wire can be run from the effected lamp to a grounding source (frame/engine). I've had this problem for years. If you find a solution please let me know. I've ripped up the wiring from just beneath the driver headlamp all the way to the other lamp. I've found tons of rotted connections, fixed them, but never the original problem. Still looking!
check your fuse for that headlight even if it is blown it will still get power because of the way the circuit is set up it is called a sneak circuit . power backfeeds through the lights causing this condition.
changing the bulb
Changing a 2007 headlight bulb is very easy. You will need to open the hood and find the bulb at the corner of the headlight assembly. Then you will turn the bulb socket counter clockwise to remove. After the bulb is out, you will replace it with a new one and screw it back into the headlight assembly.
changing head lamp bulb on Audi q7
changing head lamp bulb on audi q7
You have a broken wire.
I'd first suggest checking to make sure that no fuses or relays have popped, especially if the car's battery was not disconnected when the bulb was replaced.
Changing a headlight bulb in a 2007 Buick Lacrosse can be done easily. Just remove the cover piece and change the bulb.
Possibly the headlight relay underhood or headlight module behind glovebox
You will first need to get the right bulb--do this by checking the users manual. You can then take out the old bulb and replace the new one.
Changing the headlight bulb in a Jaguar X-Type vehicle is easy. Simply find the bulb located on either side of the car near the wing. Unscrew the bulb and replace it with a new one.
1998 Chevrolet S-10 Fuses. The fastest and easiest way to locate and identify fuses is to consult your owner's manual - always the best place to start. After checking your fuses you may find out that it's a bad bulb that's braking the circuit. If it ends up being a burnt out bulb, see sources and related links below and then consult your owner's manual for installation info.
Check the dashboard switch.These price about $50, so I personally would be heading to my favorite auto junkyard/salvage yard - especially since this is something of a guess.