See linkage below. I had a driver's side that wouldn't fold and then broke when somebody walked into it. My guess is that the internal mechanism is dislocated or out of position. There is a notch on the rotation point that might be out of position with the corresponding hole. Try gently pushing down or pulling up when trying to fold it. It's greased at the factory but the grease was long dried out and gone on mine when I got it apart 24 years later.I would be really interested in any step by step instructions, video, or pictures of how to disassemble and reassemble one of the 1995 - 96 Impala SS folding mirrors.
My passenger side mirror no longer folds. I'd like to determine why are repair it. It would seem that the only way to do that is to take the entire thing apart and grease/oil something.