Why are my Subaru headlights so dim?

Corroded Ground Wire: One of the most common causes of dim headlights is a corroded ground wire. Bad Alternator: Another very common reason to see dim headlights is a failing alternator. If you notice that the lights brighten and dim as the engine revs up and down, the alternator should be checked immediately.

Why do my headlights not work but my brights do?

By far the most common reason your brights will stop working is from a blown fuse or a bad relay. Or, it could be a bad relay. If the headlight relay has failed, it may not respond when you attempt to switch the high beams on. Replacing the relay should restore the system and get your high beams working once again.

How do you fix weak headlights?

Repair a dim headlight

1. Clean a ground cable connection. Disassemble the connection, clean it with a wire brush and reassemble it.
2. Bulb with brown/gray film. Check the bulb to see if the inside of the glass is covered with a brown/gray film.
3. New clear bulb. Replace the old bulb with a new one.

Why are my headlights still dim after replacing bulb?

Over time, your lenses can become oxidized—leading to a foggy, cloudy, or yellowed lens appearance. The opaque shade caused by oxidation does not let as much light pass through as clear lenses. This will leave your headlights looking dim, even if you have brand-new bulbs.

Do headlights dim with age?

Most headlights will dim over time. Replacing them regularly will ensure the best lighting performance. Consider replacing standard halogen headlights with high performance headlights that produce a light closer in color to natural daylight. These whiter, brighter bulbs help improve your visibility at night.

Why are my LED headlights not working?

If your LED or HID headlight bulbs are not turning on, the cause is likely a polarity issue. LED and HID bulbs are polarity sensitive, which means that if the positive doesn’t line up with the positive and the negative with the negative, no power will flow from the vehicle to the bulb.