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2008 Outback 2.5i
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Good evening everybody. This morning I ran into a problem with the headlights, specifically the low beams, on my Outback and I'm hoping someone might be able to shed some light on the situation.

After I started my car I switched on my headlights. There was a very brief but noticeable flash (brighter than the low beams are normally) but the low beams stayed on. I am sure I did not accidentally flash the high beams. Anyway, I was concerned about the unusual flash so I turned off the headlights and then turned them back on. This time the low beams did not come on at all. The high beams and fog lights, however, worked perfectly fine. So, with the car still running and the low beams switched on, I got out to check. There was no light at all, not even a faint glow, from the low beams.

Here's where, in my opinion, it gets a little weird. While out of the car I decided to try employ the standard troubleshooting technique of hitting it. Gently. And then, oddly enough, the drivers side low beam came back on! Unfortunately the same technique didn't work for the passenger side.

This all happened at 5am this morning. The drivers side low beam still works. I removed the passenger side low beam bulb and I believe that one is dead now. At least I didn't see any material connecting the filament on one side. I didn't dare remove the drivers side bulb for fear that it would break. I also checked the wiring connections as best I could at the headlights themselves. Everything looked fine there.

My best guess is that I had a power surge go to the headlights causing damage to the low beam bulbs. Is this a reasonable theory? Or is there something more likely to have caused this issue? I'd appreciate any tips regarding this issue.

Some possibly pertinent info. I was using a set of Sylvania bulbs roughly a year old. I don't know the exact model but they were brighter than standard. My car was also involved in an accident about a month and a half ago. I don't believe any of the electrical system was damaged, but I can't rule out that possibility. The lights worked fine until this morning.

Thank you in advance for any help/tips/advice!
 

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While a surge can't be discounted, that would be unusual, and it would question why other lights and functions don't seem to have been affected.

Bulbs generally tend to fail when they are turned on -- it's seen with incandescent house bulbs -- turn them on, there's a bright flash, and darkness. There's often a small weakness in the filament that becomes more significant after many hours of operation. Normally, when the current is first turned on, the resistance of the filament is lower (when it's cool) and there's a natural surge of current. This is very short-lived (the filament heats up immediately to a bright light), but the initial higher current passing through a weak point in the filament will cause it to overheat and burn out, breaking the filament at that point.

I would think the bulbs simply reached their limit of operation. One side failed fully -- there's a missing part of the filament -- while the other filament simply broke at the weak point, but your tap caused the ends to come together. It might work, but won't last.
 
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