I have recently (last week) acquired my first Mercedes- a 96 SL600 with 30k. The right low beam will sometimes flash, then go dark and the exterior light warning on the dash illuminates. By switching the lights off then on again, the condition rectifies, although sometimes I have to do this a couple of times. The lights may then operate normally for hours. This car has the xenon HID lights. Any idea what I'm dealing with here?