I have a Donnely auto dim mirror that seems to be permanently on dim even with no power applied. It is not yellowed which I know means that the gel inside has failed. It is just a dark blue. I can see out during the day, it is like a tinted rear window. and at night it does seem to darken as a car comes up with its headlights on. So my question is: Is the mirror going to fail and should I be concerned, does it need repair, or just let it go?