1997 S-10 P/UP 4cyl Dome Light flicker during Driving

Dome light keeps flickering on and off while driving. I hear the clicking by the switch (near fuse access box under dash by drivers door). The switch was replaced when some body repair was conducted. Seems to be connected correctly. Although it's tight getting to it. I've heard that bad door bushings may be a possible culprit. How do I know? Any tips/tricks to troubleshoot or replace the bushings or switch?

P.S. Fuse is good. Dome & interior lights turn on when door is opened. Turn off when closed until I drive down the road a piece.

Thanks

Bob