1998 S-15 Sonoma headlight issue

Ok, I thought I was in the clear after the Blazer HVAC thing but now my brothers S-15 is having headlight issues. The other day he hit a guard rail on the freeway after he was cut off by some numbnuts and hit black ice launching him passenger side first into the guard rail. It crumpled the fender and the bumper. Now the passenger side headlights are really dim and when he puts on the brights only the drivers side switches to bright while the passenger side gets even dimmer. I pulled the headlight assembly and found three pinched wires which I fixed but didnt help. So I pulled the battery and tray and repaired the ground wires that are under the tray, I even drilled and used fresh bolts for a good clean ground and that didnt help. So we swapped the drivers side lights with the passenger side lights thinking maybe something was wrong with the bulbs but didnt help. I am at a loss now. Any words of wisdom from the gurus?

You're on the right track. Without a doubt, it's a ground problem with the right side headlight. Check resistance from the headlight socket ground terminal to body ground, it should be less than 5 ohms.