Dimming Headlights

I have a 1990 Ford Ranger with 216K miles. Over the last few years, the headlights have become dimmer and dimmer. Does anyone know what is wrong and how to fix it? Thanks!

Have you tried replacing the headlight lamps?

Headlight lamps can become dimmer as they age.


I would suspect a corroded ground connection. Check the ground connection to the chassis from the battery and locate where the headlights are grounded to the body. Clean these ground connections. After 23 years, it is entirely possible that these connections may show some corrosion,

Are the headlights the kind where you just replace the bulb when it burns out, not the whole lens unit? If so, its possible the lens is dirty on the inside. Or the outside of the lens had become pitted. Do you drive in an area that is dusty or where there are sandstorms or dirt devils? If this were my car & I’d eliminated the above, I’d either just replace the bulbs, or I’d probably do an experiment where I compared the brightness on the car vs off the car, jumpered directly from the battery.

Are these sealed beam headlights? Trucks used them long after cars went to composite headlights. In the old days of sealed beams, the filament would burn out so they had to be replaced every couple years. When halogen technology was introduced into the sealed beams, the bulbs lasted much longer.

I have found that in addition to a slight reduction from the halogen tubes, the reflective surface at the back of the bulb degrades too. I had one set of sealed beams last so long that the reflective coating completely degraded and the headlights did a better job of lighting up the engine compartment than they did the road ahead.

Cars and trucks behind me lit the road in front of me better than my headlights did. In fact, it looked like my headlights were casting a shadow in the light beam of other vehicles.

Are the headlight lenses cloudy? That could be part of it. I’d be surprised if the headlights are original. But you could trY replacing them.

My guess is that a 1990 Ford Ranger has sealed beam headlights. I say this because my 1990 Ford Aerostar had sealed beam headlights. These lights are readily available and not expensive. It’s worth a shot to see if the new sealed beam units are brighter.

The only thing I have not done is track down the ground. I will try that this weekend. Appreciate all your help! Thanks!