The new paint is probably the culprit blocking the ground path for the headlights, causing them to dim. You can scrape a little paint off in the headlight bar socket, where the headlight attaches, and under the carriage bolt head where the bar bolts to the fender, and on the fender brace where the nut for the carriage bolt goes so that you have an unbroke metal to metal ground path. Is the wire coming off the generator only getting warm when you turn your headlights on?