I have an '03 GMC 2500 HD with about 1500 miles on it. At night with the headlights on it does its own "flash to pass" with the bright lights. Sometimes it flashes fast, sometimes it comes on and stays on, sometimes it flashes slow, and sometimes it doesn't do it at all. It seems to be getting worse and I fear it may be hard for the dealer to find with it being so intermittent. Have you had any experience with this type of problem before? I keep having people pull over in front of me thinking I'm flagging them down. I was really just hoping to have a better diagnosis before I even call the dealer.