Outer Limits 4x4 Board

I'm having a weird problem with my headlights. My low beam on the right side doesn't work but the high beam works OK. The left side light works fine for both low/high.

I did install a wiring upgrade last year and thought it may have been that. I plugged my factory plug back in but the low beam is still dead.

Does the H4 bulb have 2 seperate circuits? Could the low beam circuit have failed but the high beam circuit still be OK? I was going to swap left and right bulbs over but I've run out of light, literally.

Yes, the H4 bulb has two separate filaments, one for high beam and one for low beam. High beam is across the two outside pins, low beam is between middle pin and one outside pin (I don't remember which one.) If you have a multimeter, check for continuity between the middle pin and either end (doesn't matter which - you'll either go direct across the low beam filament, or across both filaments in series). If there's no continuity, that's your problem.

Always check the globe first. KISS princaple