I have a HID kit fitted to the car and its been on for about a year and a half. Sometimes when I put the head lights on they both work and sometimes the pass side doesnt. I swapped the bulbs over to eliminate a faulty bulb. I also took the headlight out and checked all the plugs and they seem fine. Would a faulty ballast cause this? I think it seems like a dodgy connection but since checking I am not sure now. Cheers.