Sounds like a classic case of the wiring harness just inside the inner wing becoming chaffed on the metal work. There are some rough/exposed welding and seams just where the wiring for the lights disappears into the bumper from the engine bay and over time this wiring can often rub through. Once shorting out on the metalwork all manner of peculiar happenings can occur with your lights.
All that is needed is to repair any broken or chaffed wires and suitably protect them from future wear and tear by way of wrapping them up in some insulation or fixing some insulation over the rough edges on the metalwork. Access is best with the front bumper removed but you can get to it from underneath the car by removing the small panels that cover the outer regions of the underside of the bumper (car up on axle stands/ramps, of course).
Hope that helps.
