On my 2002 beetle, my driver side dim headlight is very dim. I replaced it with a new H1 and that one to is dim. When I turn the brights on, it is the same as the passengers side. Anybody see this before or know what is wrong??
When you replaced the bulb, what was the condition of the little wiring harness inside the headlight? These wires tend to get cooked pretty good. It could be that most of the strands in one of the wires have been cut.
It sounds like problem is in electrical system not the bulb, since new bulb didn't fix it.
I have had a similar problem as yours going on on my 2002 1.8T for quite sometimes.
...dim headlights, horn not so loud, melted 150A fuse & fuse block on top of battery, and some power loss...
After days of analysis, the problem was fixed with the cost of one fuse and a piece of sand paper.
I removed the big black wire on the far left of fuse block on top of battery,
used metal sand paper to clean oxidized contact surface on its terminal,
and put it back with a new 150A fuse, tighten it very tightly.
Once electrical current flows well, all problems above were solved with a bonus of a little better gas mileage.
It's been two weeks now and everything is still looking good.
I was lucky it's not something bigger and costlier.
Check your ground wires on the headlight harness.. I had this issue when I made my own headlight harness from thicker wire due to my OEM harness crumbling and falling apart. Re-soldered the ground wire and it worked.