Need help, I have the stacked headlight set or quad lights on my 84 Silverado. The headlights are dim on the driver's side only. I checked the ground - no luck!
Also, I just upgraded the headlights to the plastic LEDs. , also no change. ..Any ideas?

 

since the passengers side pulls from the drivers side its possible to have a poor connection just on the drivers side spade connector inside the pigtail where it connects to the headlight. do you have any other light issues?
typically with grounding issues they cause all sorts of issues light turn signals dont work properly when the headlights are on or all the lights flash. also are yous set up so all 4 headlights come on when the high beams are on?
and is the dim lights both with the low and high?

 

No, I don't have any other light issues, but I did notice there's less than 12 volts at the light. I have tested the passenger side yet, but I did connect the drivers side lights directly to the battery, with no change.