Home CAR GUIDE How to Check Car Rear-view Mirror

How to Check Car Rear-view Mirror

rear-view mirror (or rear-view mirror) is a convex mirror in automobiles and other vehicles which are designed to allow the driver to see back through the vehicle’s rear window (rear windshield).

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Rear view mirror is a device that helps the driver to see backward. It generally finds its place at the top of windscreen inside the cabin. This device is one of the most basic but important safety devices in the vehicle. It provides assistance to the driver while overtaking, parking in reverse gear, etc. Generally, vehicles also have a pair of mirrors which is attached to the body from outside. They are usually called ‘side mirrors’ or Outer Rear View Mirrors (ORVM) which serve the same purpose.

An anchor holds the rear view mirror to the windscreen with the help of a special type of joint called ‘swivel’ joint. It allows the driver in adjusting the mirror according to his/her seating position. Nowadays, manufacturers make mirrors with a convex lens as compared to the plain glass which was used earlier. Use of the convex lens has substantially increased the capacity of mirrors for grasping the distant images.

Symptoms of a Bad or Failing Rear-view Mirror

If you notice the auto dimming is not working, the rear-view mirror is discolored, or the mirror is missing, have the rear-view mirror replaced.

The mirror should last the lifetime of your vehicle, but there are a few things that can lead to malfunction. Look for the following symptoms if you suspect a bad or failing rear-view mirror:

1. Auto-dimming does not work

If the auto dimming feature does not work, the sensors might be off. There are several sensors that are found on the back of the mirror. Find them and clean them with a soft cloth in order to avoid scratching. Ensure there is nothing blocking the light from the sensors. After cleaning and inspecting them, shine a flashlight on the sensors to see if the mirror dims. If it does not dim, your rear-view mirror might not be working properly and has to be replaced.

2. Discoloration

Over time, the sun and other debris that continuously touch the rear-view mirror might be making it discolored. If this happens, just try to clean it with a soft cloth. Again, use a soft cloth so that you do not scratch the surface. The discoloration can be below the surface of the mirror too. If the discoloration does not come off, chances are the mirror has been damaged beyond repair and has to be replaced.

3. No rear-view mirror

 Sometimes accidents can take place and the rear-view mirror might fall off or breaks off from its mount. When this happens, it has to be replaced as soon as possible. Some states have laws requiring a rear-view mirror, so make sure to replace it as soon as possible.

How to Replace a Rear-view Mirror

A) Verify the door mirror’s condition

Step 1- Locate the rear view mirror that is broken or cracked.

•    Check the rear-view mirror for any exterior damage.

•    For electronically adjusting mirrors, you need to gently tilt up, down, left, and right on the mirror glass to see if there is any binding of the mechanism within the mirror.

•    On other mirrors, you have to feel the glass to see if it is loose and can move around or if the housing moves around.

Step 2- On electronic rear view mirrors, locate the mirror adjusting switch.

Move the selector or push on the buttons to verify the electronics work on the mirror mechanics.

Step 3- Determine if buttons work.

For the mirrors with the clock, radio, or temperature, just check the buttons to see if they function correctly.

B) Replacing a rear-view mirror

Materials Required

  • Allen wrench set
  • Clear silicone
  • Cross tip screwdriver
  • Disposable gloves
  • Electrical cleaner
  • Flat tip screwdriver
  • Permanent marker
  • Ratchet with metric and standard sockets
  • Torque bit set
  • Wheel Chocks

Step 1

Park your vehicle on a flat and hard surface.

Step 2- Place wheel chocks around tires.

Lift the parking brake to the lock the rear tires from moving.

Step 3- Put a nine-volt battery saver into your cigarette lighter.

•    This helps to keep your computer live and keep your current setting in the vehicle.

•    It’s fine even if you do not have a nine-volt battery saver.

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Step 4- Disconnect the battery.

•    Open the vehicle’s hood for disconnecting your battery.

•    Take the ground cable off from the battery’s negative post disabling the power to the vehicle.

For standard DOT, wide DOT, wide with deflector DOT, and custom design mirrors-

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Step 5- Unscrew the mounting screw.

Unscrew it from the base of the mirror and attach it to the windshield. Ensure to take the screw out of the mirror housing.

Step 6

Lift the mirror up off from the mounting plate.

For electric DOT mirrors-

Step 7- Unscrew the mounting screws.

•    Unscrew them from the base of the mirror attaching to the windshield.

•    Take the screws out of the mirror housing.

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Step 8- Remove the harness plug from the mirror.

Use an electrical cleaner to clean the harness as well as remove any moisture or debris.

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Step 9- Use a blow dryer or heat gun to heat up the mounting plate.

•    When the mounting plate is warm to the touch, just move it back and forth.

•    Eventually, after moving it a few times, the mounting plate will come off.

Step 10- Mark the original location of the mirror.

•    Before removing all of the adhesive, utilize a grease pencil or permanent marker to mark the original location of the mirror.

•    Make the mark on the outside of the glass so you do not have to remove it when cleaning off the adhesive.

Step 11- Use a razor scraper for removing the remaining glue from the glass.

•    Place the edge of the blade on the glass and continue scraping till the surface is smooth again.

•    Leave the mounting plate attached inside the bracket on the mirror, use the scraper for removing any remaining adhesive.

Step 12- Remove any dust.

•    Wet a lint-free cloth with isopropyl alcohol, and wipe the inside of the glass in order to remove any dust remaining after scraping the adhesive.

•    Allow the alcohol to evaporate completely before you proceed to attach a mirror to the glass.

Note: You will need to apply isopropyl alcohol to the mounting plate if you plan on reusing the plate.

On a custom cab fit and bus DOT-

Step 13- Unscrew the mounting screws.

•    Unscrew them from the base of the mirror attached to the cab.

•    Take the screws out of the mirror housing.

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Step 14- Remove the mirror.

In case of any gaskets, just remove them.

Step 15- Get your adhesive from the rear-view-mirror adhesive kit.

•    Apply the adhesive on the back of the mounting plate.

•    Place the mounting plate on the area of the glass where you have marked it.

Step 16- Press gently on the mounting plate to seat the glue.

This heats up the glue and removes all air from it for the purpose of drying.

On standard DOT, wide DOT, wide with deflector DOT, and custom design mirrors-

Step 17- Place the mirror onto the mounting plate.

Slide the mirror into a place where it fits firmly and is not able to move.

Step 18- Put the mounting screw into the base of the mirror with clear silicone.

Tight the screw properly.

Note: The clear silicone on the mirror mounting screw will keep the screw from backing out, but will make it easy to remove the next time you might need to change the mirror.

For electric DOT mirrors-

Step 19- Put the mirror onto the mounting plate.

Slide the mirror into a place where it fits properly and does not move.

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Step 20- Install the harness onto the mirror plug.

Make sure that the lock clicks into place.

Step 21- Put the mounting screw into the base of the mirror with clear silicone.

Tight the screw properly.

On custom cab fit as well as bus DOT mirrors-

Step 22- Install the mirror and gaskets if any onto the cab.

Screw in the mounting screws with clear silicone into the base of the mirror attached it to the cab.

Step 23- Tighten the mounting screws hand tight.

Remove the mirror as well as the gaskets if there are any.

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Step 24- Reconnect the ground cable back onto the battery’s negative post.

Detach the nine-volt battery saver from the cigarette lighter.

Note: If you did not have a nine-volt battery saver, you will have to reset all of the Settings in the vehicle, like your radio, electric seats, as well as the electric mirrors.

Step 25: Tighten the battery clamp.

Make sure that the connection is good.

C) Testing the rear-view mirror

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For standard DOT, wide DOT, wide with deflector DOT, and custom design mirrors-

Step 1- Move the mirror up, down, left, and right to check for proper movement.

Check the mirror glass to make sure that it is tight and clean.

For electric DOT mirrors-

Step 2- Operate the adjusting switch to move the mirror up, down, left, and right.

Check the glass to make sure it is fastened securely to the motor in the mirror housing. Ensure that the mirror glass is clean.

Video of How to Replace a Rear-View Mirror

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