how to fix auto dimming rear view mirror

If the auto-dimming feature on your rearview mirror is not functioning correctly, it can be due to several reasons, such as damage to the mirror, electrical issues, or sensor problems. Here are some steps to diagnose and potentially fix a malfunctioning auto-dimming rearview mirror:

Note: The specific steps and solutions may vary depending on the make and model of your vehicle. Consult your vehicle’s owner’s manual for model-specific instructions.

Materials You May Need:

  1. Safety gear: Safety goggles and work gloves (optional).
  2. Screwdriver set: To remove and access the mirror.
  3. Electrical cleaner or contact cleaner (if needed): For cleaning electrical connections.
  4. Replacement mirror (if needed): If the mirror is damaged or beyond repair.
  5. Multimeter (optional): To test electrical components (if you have electrical knowledge).


  1. Safety Precautions:
    • Ensure that the vehicle is parked safely, and the ignition is turned off.
    • Consider wearing safety goggles and gloves, especially if you’ll be working with electrical connections.
  2. Assess the Issue:
    • Determine the specific problem with the auto-dimming feature. Is the mirror not dimming at all, or is it dimming too much? Does it only malfunction during certain conditions (e.g., at night or in bright sunlight)?
  3. Clean the Mirror:
    • Start by cleaning the mirror’s surface on both sides (front and rear) to ensure there are no contaminants or smudges affecting its function.
  4. Inspect Electrical Connections:
    • Check the electrical connections of the mirror. Locate the wiring harness or connector that attaches the mirror to the vehicle’s electrical system. Ensure that it is securely connected and free from corrosion or damage.
  5. Test the Auto-Dimming Feature:
    • With the vehicle’s ignition turned on, cover the sensor on the back of the mirror (usually a small, round sensor). This sensor detects light and triggers the auto-dimming feature. If the mirror begins to dim, it means the sensor is working correctly.
    • If the sensor doesn’t respond, it may be faulty and require replacement.
  6. Inspect the Mirror’s Surface:
    • Carefully examine the mirror’s surface for any damage, such as cracks, delamination, or discoloration. If the mirror is physically damaged or the dimming layer is compromised, it may need replacement.
  7. Check for Electrical Issues:
    • If you have electrical knowledge and access to a multimeter, you can test the electrical components of the mirror, such as the power supply and circuitry. Be cautious when working with electrical components, and refer to the vehicle’s wiring diagrams for guidance.
  8. Replace the Mirror (if needed):
    • If the mirror is physically damaged or you’ve determined that it cannot be repaired, you may need to replace it. Purchase a compatible replacement mirror from an auto parts store or a dealership.
  9. Installation of Replacement Mirror:
    • Follow the manufacturer’s instructions for installing the replacement mirror, ensuring all electrical connections are secure.
  10. Test the New Mirror:
    • After installing the replacement mirror, test the auto-dimming feature to ensure it functions correctly.
  11. Consult a Professional (if needed):
    • If you are unable to diagnose or resolve the issue on your own, or if you are uncomfortable working with electrical components, consider seeking assistance from a qualified automotive technician or a dealership.

Properly functioning auto-dimming rearview mirrors can enhance driving safety by reducing glare from headlights behind you. If you are unable to resolve the issue on your own, it’s important to have the mirror inspected and repaired by a professional to ensure your safety on the road.