passenger headlight out, but brights work fine

[doood]

I may have been driving for a while with only driver-side headlight. I saw tonight that my passenger side headlight is out, but when I hit the brights, all four headlights shine (1984 Monte Carlo).

Is the problem likely in the headlight switch in the dash? There is no separate filament for the high beam, right? If the bulb lights on high beam, it should light on low beam, right?

Could I have knocked something loose behind the radio? I found some funky wiring back there; hard to believe it came from the factory that way, but the electrical tape was ancient and the stereo is original.

 

[oldsmobile joe]

There is no separate filament for the high beam, right? If the bulb lights on high beam, it should light on low beam, right?

Your low beam bulb has separate low and high filaments. Hence the three wires that go to it.

 

[doood]

Your low beam bulb has separate low and high filaments. Hence the three wires that go to it.

I did not know. The bulbs are original. I've replaced exactly one headlight in my life, and it was on a Ford Tempo, in the year 2000.

Thank you very much. I'll take being a moron any day over chasing down an open circuit in a bird's nest of wires...

Thanks. Mike