2018-2020 Acura RLX Rear View Mirror: Auto-Dimming Failure, Leaks, and Replacement
This guide covers the common leaking and failure of the auto-dimming feature, how to replace the mirror yourself, and what to inspect when buying a used unit.
- The primary failure mode is the auto-dimming fluid leaking internally, creating a 'bubble' in the glass. This fluid is corrosive and can damage your car's interior.
- A new OEM mirror is extremely expensive (over $800), making a quality used OEM part the most cost-effective solution.
- When buying used, always inspect the glass for the tell-tale bubble or fluid line to ensure it hasn't already failed.
- Replacement is a very simple DIY job that takes less than 20 minutes and requires only a trim tool.
Symptoms of a Failing Rear View Mirror
The most common issues with the 2018-2020 Acura RLX interior mirror are related to the failure of its auto-dimming technology. Because this is an electronic part, other failures can also occur.
Auto-Dimming Fluid Leak or Failure
The electrochromic gel used for the auto-dimming feature can break down over time. The seal between the glass layers fails, allowing the gel to degrade and leak. Symptoms include:
- A "bubble" or distinct line in the mirror: You may see what looks like a large air bubble or a clear separation between a normal mirror area and a discolored, yellowish area. This is the most obvious sign of failure.
- Leaking fluid: An oily, yellowish fluid may leak from the bottom of the mirror housing. This fluid is corrosive and can permanently damage the plastic on your center console or stain leather seats if it drips.
- Failure to dim: The mirror no longer darkens when bright headlights shine on it, making night driving less comfortable.
- Flickering or inconsistent dimming: The dimming function may work intermittently or flicker, which can be a sign of a failing sensor or internal wiring.
Warning: If you notice fluid leaking from your mirror, place a towel on the center console immediately to prevent damage. The electrochromic fluid can eat away at plastic trim finishes.
Electrical and Button Failures
Less common, but still possible, are general electrical failures. This can include the HomeLink garage door opener buttons ceasing to function or the entire mirror losing power (indicated by the green power light not turning on). This could be caused by a bad connection at the mirror's plug or an internal circuit board failure.
Buying a Used Interior Rear View Mirror for 2018-2020 Acura RLX
Due to the extremely high cost of a new OEM mirror, a used part is the most practical option for most owners. However, it's crucial to inspect the part carefully to avoid buying one that has already failed.
What to Inspect on a Used Mirror
- Check for the Bubble: Hold the mirror up to a light and tilt it around. Look for any signs of the internal fluid separating, which appears as a bubble or a sharp line across the glass. Do not buy a mirror that shows this, as it has already failed.
- Examine the Seams: Check the edges of the glass and the bottom of the plastic housing for any oily residue, which indicates a past or current leak.
- Verify the Part Number: Ensure the part is OEM number 76400-TY2-A11. This ensures perfect compatibility with the vehicle's wiring and mounting system.
- Inspect the Connector: Look at the electrical connector pins to ensure they are straight and free of corrosion.
- Test the Buttons: If possible, press the HomeLink and power buttons. They should have a solid, tactile click.
Pro Tip: A used OEM mirror is a significantly better choice than a generic aftermarket one. For this specific part, direct-fit aftermarket options are not readily available. A genuine Acura mirror guarantees the auto-dimming and HomeLink features will work correctly and that the mirror will mount securely without vibration.
Replacement Guide
Replacing the interior rear-view mirror on an RLX is a straightforward job that most DIYers can complete in under 20 minutes. A video demonstrating the process on a 2018 RLX confirms the simple procedure.
- Remove the Plastic Cover: Behind the mirror base where it meets the windshield, there is a two-piece plastic cover. Use a plastic trim tool to gently pry the cover closest to the headliner off first. Then, pull the larger piece straight down; it is held by four clips.
- Disconnect the Electrical Plug: With the cover removed, you will see a single electrical connector plugged into the mirror. Press the release tab and unplug it.
- Remove the Mirror: Firmly grip the base of the mirror and twist it about 45-90 degrees to the left (counter-clockwise). It will release from the metal mounting button that is glued to the windshield.
- Install the New Mirror: Align the new mirror onto the windshield button and twist it to the right (clockwise) until it locks firmly in place.
- Reconnect and Reassemble: Plug in the electrical connector until it clicks. Snap the plastic covers back into place.
Recalls and Technical Service Bulletins (TSBs)
As of mid-2026, there are no recalls or TSBs issued by Acura or the NHTSA specifically for the interior rear-view mirror on 2018-2020 Acura RLX models. The vehicle has been subject to other recalls, most notably for a failing fuel pump, but these do not pertain to the mirror.
Cost Comparison
The cost of a new OEM mirror from Acura is very high, making used parts an attractive alternative.
| Part Type | Estimated Cost |
|---|---|
| New OEM | $820 - $1,235 |
| New Aftermarket | Not Available |
| Used OEM | $50 - $200 |
| Shop Labor | $60 - $120 |
Frequently Asked Questions (FAQ)
How do I program the HomeLink garage door opener buttons?
To program HomeLink, park your car outside the garage. First, clear any old codes by pressing and holding the two outer HomeLink buttons until the indicator light blinks rapidly. Then, hold your original garage door remote 1-3 inches from the mirror. Press and hold both the remote button and the HomeLink button you wish to program. The indicator light will flash slowly, then rapidly. Once it flashes rapidly, both buttons can be released. If your garage has a rolling code system, you may also need to press the 'Learn' button on the garage door opener motor unit itself and then press the programmed HomeLink button in the car within 30 seconds.
Is the leaking mirror fluid dangerous?
The electrochromic fluid is a chemical irritant and is corrosive to plastic and leather surfaces. While it's unlikely to cause serious harm from brief skin contact, it should be cleaned up promptly with gloves. The primary danger is the permanent damage it can cause to your car's interior trim.
Can I just install a cheaper, non-dimming mirror?
While physically possible, it is not recommended. The vehicle is wired for the powered, auto-dimming mirror. Installing a basic mirror would mean the electrical connector would have nowhere to plug in, and you would lose the HomeLink functionality. It's better to find a functional used OEM mirror.
Is the mirror the same for the RLX and the RLX Sport Hybrid?
Yes, the interior rear-view mirror with part number 76400-TY2-A11 fits all trims of the 2018, 2019, and 2020 Acura RLX, including the base and the Sport Hybrid SH-AWD models.
Technical Specifications
OEM Part Numbers: 76400-TY2-A11 76400TY2A11
Features: Auto-Dimming, HomeLink Universal Transceiver. Mount: Twist-lock cam type. Connector: Single multi-pin electrical connector.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Acura RLX:
- 🛍️ Shop This Part
- Symptoms of a Failing Rear View Mirror
- Auto-Dimming Fluid Leak or Failure
- Electrical and Button Failures
- Buying a Used Interior Rear View Mirror for 2018-2020 Acura RLX
- What to Inspect on a Used Mirror
- Replacement Guide
- Recalls and Technical Service Bulletins (TSBs)
- Cost Comparison
- Frequently Asked Questions (FAQ)
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