Low-beam headlamp mystery?

[chiguy]

Okay, I've read all the old threads on "low beams don't work, high beams do" but I still seem to have a mystery here. My 12 year old (95) Subaru Legacy wagon has just recently taken to eating headlamps. The original set lasted probably 10 years and now it has gone through 3 sets in a year. Each time, the low beams go and the high beams still work. The bulbs look fine, just a small break in the low beam filament. The fuses and relays seem fine. I run with my lights on all the time for visibility, basically like running lights and they seem fine until a long drive. I routinely make about a four hour drive for work every few weeks and maybe it's coincedence, but they always seem to go on that trip. At first, I thought I had a wiring problem, but decided to try new bulbs just to check and sure enough, they worked. That's when I looked extra close at the old bulbs and realized the filaments were shot on the low beams. So, I'm guessing there is some sort of wiring issue causing this, but wondering if anyone has any ideas where to start looking.

[Cougar]

I can't think of anthing with the wiring that would do this unless the supply voltage is too high. Have you checked that? If that isn't more than 14.8 volts then you might try another brand of bulbs.

[Tech1967]

And if that fails find your ground points and clean them up. This should be followed with some praying.

[Suzam]

Make sure your headlamp plugs are in good shape too and making good contact, it's the top one for the low beam.

 

I went through a series of bulbs, and went to other suppliers after the ones I got at Pep Boys kept blowing out.

 

If they are mistreated being shipped to the store or packaged poorly, it only takes a few good bangs of the box they are in to shorten the life.

 

Don't forget to be careful to keep your fingers off them. Oil from your skin shortens the life also.