Your car's various mirrors provide you with a critical view of the areas surrounding the vehicle. Without fully functioning side or rear view mirrors, you won't be able to see if you're about to hit an object or a pedestrian while driving or parking. This is why it's very important to troubleshoot mirror problems early on. To help you out, here are some of the most common problems and what you can do to solve them:
Whether they're on your rear view or side view mirrors, water spots are not just annoying; they actually obscure your view, putting you, other drivers, and pedestrians at risk. Fortunately, getting rid of these spots is easy. You just need an auto glass cleaner that's alcohol- and ammonia-free. Spray some of this on a lint-free cloth and rub it on the damaged area. Rub until the spots disappear. After letting the surface dry, wipe the glass with another piece of clean cloth.
The right solution for scratched mirrors depends on the severity of damage. If the scratches are small and shallow, you can polish them out with a glass buffing compound. A cheaper alternative is jewelers' rouge. Another cheap alternative is toothpaste since this is a mild abrasive. Apply a small amount of buffing compound, jewelers' rouge, or toothpaste on the scratched area. Polish the scratches with a buffer until they disappear. Now if the scratch is big and deep, you won't be able to buff it out; the solution here is to replace the mirror.
Loose or wobbly mirror assembly
If the rear view or side view mirror assembly becomes loose, you need to examine first if the unit is completely broken or is just missing a few screws. If it's completely ruined (i.e. the side view glass was accidentally smashed by a cyclist), of course you have to replace the whole assembly. But if it's just a matter of loose or missing screws, you just need to remove the covering or cap, find the holes for the screws, and attach or tighten the screws.
Now if the actual glass becomes dislodged or loose, you can always glue it back in place with an automotive grade adhesive.
Malfunctioning auto-dimming features
Many newer models today sport auto-dimming features that are especially useful when reducing glare. Some even have additional electronic capabilities that allow these mirrors to digitally display the time, temperature, and driving direction. If you have one of these devices but you can't see the displays, you have a problem with the wiring. Check if the wiring connections aren't damaged or disconnected. If the wires aren't damaged, take a look at the glass and see if it's cracked or cloudy. Cracks and water spots can be easily removed with a glass cleaner and buffer.
Now if the problem is an auto-dimming mirror that won't dim properly, check the sensors for signs of damage or dirt. If they're busted, these sensors will have to be replaced to get the auto dimming feature working. If they're just dirty, clean them with a microfiber cloth.