Try this, I learned it here. Rotate the copper bulb retainer. It contacts/grounds with the housing and sometimes corrosion builds up between the two. It doesn't rotate much just wiggle it back and forth. Hopr the description is one you can understand. Hope this is it. Good luck. Pete
67 red camaro convertible, 78 silver anniversary vette, 1976 kz900, 1985 Z28 camaro, 1971 chevelle. Too many toys now My four car garage is no longer big enough.