One of my headlights is shorted so that both the dim and bright filaments light at the same time resulting in a dim light. Any suggestions where to begin to troubleshoot?
Sounds more like a bad ground. This can cause the electricity to feed back through the other filament. Check that the connector going to the light with the problem is in good shape. One of those wires in the connector is a ground. Follow it and make sure the ground connection is tight and clean.