Correcting Very Dim GMC Safari / Chevy Astro Seamed Beam Headlight - Let's Figure This Out

I usually don't drive my 1997 GMC Safari at night. The other night we were coming home from the airport and were taking backroads which have no street lighting.

The headlights on the van were awful. It appeared only the passenger headlight was working but when we got home I check and both were working. Well, sort of. The driver's side headlight was considerable dimmer.