xjs headlight problem

I have a 1994 Xjs and my head lights would be on dim and all by themselves they would switch to bright and from that point on they go back and forth by themselves. The high beam on the dash also signals that they are on and then goes off as they go back to dim. The problem is getting worse and its to the point where most of the time they stay on bright. I'm getting an awful lot of finger gestures from this problem.