Classic/Antique Car Repair: Dim Headlights, running gear, headlights

Question
I have a 1938 Dodge with updated running gear.  Alternator and battery are good but headlights are dim.  BUT, if you disconnect one of the headlights the other one comes on bright as it should.  The car has the original wiring. What can I do to remedy the problem?  Thank You for your answer in advance.

Answer
It sound like a bad ground on the head light system. Check all the connections. Not just for tightness but remove the wires and make sure that the connection is not growing corrosion or rust. Clean all the connection bright and shiny clean and re attach. That includes where the grounds attach to sheet metal or the engine block or frame.
Brad