Reply to "Dim headlightlights"

The ground for the front lights is on the main stud under the dash. That stud is impossible to find until you recognize that it is actually a two-ended stud; the other end is the where the battery ground cable attaches. There are numerous ground wires from all around the front half of the car that converge on this single stud, which is virtually impossible to reach because it's blocked by the heater box, etc.

Chances are, your problems are not caused back there, but rather at the pigtail connection up front. The headlights have a fairly short harness (perhaps a foot long) that then plugs into the main harness; lots of opportunity for corrosion, etc. at either that connection or where the harness plugs
into the back of the headlights. Time spent separating those connections (four in total, two on each side) and thoroughly cleaning them out, is time well-spent indeed.

Some advocate unplugging the ground wire from the connector and grounding it locally to the body, instead of running the ground all the way back around the car to the post in the cabin. Perhaps that's something to consider if simply cleaning the existing connections doesn't work. I did this with my car and it seemed to help a bit.

You might also check the voltage going into and out of the headlight relays. It's possible you have a fault there.

I'm sure others who are more electrically inclined will offer more and better solutions.