First, test the bulbs. "New" and "good" are not always the same. A hot battery and a set of jumper wires is the most effective method. How did you get inside the dimmer switch to clean the contacts? The ones where the wires attach usually aren't the source of a problem. Once you're sure the components are good and working properly, start wringing out wiring with an ice pick test light. Be absolutely sure the grounds for both headlights are clean, tight and not corroded. Getting voltage to the lights is only half the battle- - - -the current has to find its way back to the battery.
Jerry
