After years of trouble free driving, I now have two issues going on. The first is a A/C problem which I have posted separately. This is the other one. The vehicle is a standard length 2005 T'Blazer with the straight 6 engine. Just recently, I have a strange thing happening where I hear a chime, and the dome lights at the top of the windshield between the sun visors will come on quickly and go out. It happens usually over a large bump, but on occasion, it will happen on the highway with no associated bump to cause it. I thought maybe a bad door switch, but in trying to narrow things down I opened a door while driving, and that causes no chime to sound. It happens too quickly to see if any dash indicator comes on, by the time it happens and I look down at the cluster the event is over. If anyone has any ideas on this, I would sure appreciate hearing from you. Thanks.