Only One low beam light works but all high beam lights work

[bperri1]

I have an 84' K20 with quad headlights in the front. When I turn on the head  lights only the passenger side low beam works. Replaced the driver bulb and no light. The weird thing is when I turn the high beam switch on, all four of the head lights work. (the lows and highs) My truck is the 6.2l diesel if that makes a difference in wiring.

[Captkaos]

Did you get the right bulb for that side with dual elements?

[bperri1]

Hey thanks for the reply!
T he low beam is a dual bulb?   Can you find these at a general auto parts store?

[bd]

The upper lamps (4656 high/low beam) have three terminals apiece; the lower lamps (4651 high beam, only) have two terminals apiece.

[bperri1]

Okay I'll make sure I bought the correct one. Thanks!