HEADLIGHT LOW BEAM SHORT

[EUROPEANLOVER]

I have a 2003 x5 with the 3.0. I have had the vehicle now for 2 years. I bought it with 46,000+ and it now has 76,000+. I change the oil once a year and have had no problems with the vehicle except for this one annoying electrical short. It seems to happen once every 2 to 3 months. My headlight switch is allways left in auto. My left side headlight low beam bulb will blow, i replace it, then a few months later, the other one will blow, i replace it. this goes back and forth about once every 2 months. First left side, then right side, back and forth. I used to replace the bulb that blew but was then told to replace both at the same time, still no difference and i have no condensation in the headlight assembly. Can somebody please give me some insight to what this problem might be. Can you imagine i have been changing bulbs since i have had the SAV. It's getting expensive.