The drivers side headlight on my 85 is extremely dim, But the odd part is when i turn on my brights it almost goes completely off and the left side is the only one that gets brighter.

Is this a wiring harness issue? a ballast issue? or is it the lights themselves?

Im planning to switch the lights from left to right to see if that does anything this afternoon but dident know if anyone else had experienced this before.

Thanks

 

I would think that switching the lights from one side to the other would be the place to start. If the problem "moves", then it's the light. I guess you realize this, though. I've wondered about the 30 year old wiring throughout the car myself. My car lives in the garage, and the previous owner kept it covered, too. But still, it's 30 years old......

 

Remove the driver's side headlight and replace it. When doing so inspect the connector that plugs into the bulb. The bulb is a sealed beam unit with a three pin connector. Inspect the female pins inside of the connector for corrosion and check the wiring for any breaks. Chances are you have a poor connection at the bulb causing a dim light or a failing low beam. It also sounds like the high beam portion of the bulb has failed. This would be why the light turns off when the bright lights are activated.