Acura NSX Brake Lights Not Working - How To Diagnose And Fix

By Nick Marchenko, PhD

When your Acura RDX brake light fails, it's not just an inconvenience—it's a safety issue. Fortunately, with some patience and a bit of DIY spirit, most drivers can tackle this problem without a trip to the mechanic. This guide amalgamates advice from various threads and discussions, providing a comprehensive approach to diagnosing and fixing your brake light issue.

Step 1: Initial Diagnosis

Begin by checking the brake light bulbs. Swap bulbs between the sides to confirm if the issue is with the bulb itself. If the problem persists on one side regardless of the bulb, the issue likely lies elsewhere.

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• 2020;
• 2019;
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Step 2: Inspect the Wiring

Open the trunk and remove the lining to access the back of the taillights and the wiring harness. The wiring typically runs from one side of the vehicle to the other. Since one brake light is working, focus on the wiring connected to the malfunctioning light. Look for +12v on the green/white wire when the brake pedal is pressed. If there's power, the problem might be the brake light failure sensor or a grounding issue.

Step 3: Check the Brake Light Failure Sensor

The sensor is a small rectangular box located near the taillight. It's possible for this sensor to fail, disconnecting the power supply to the bulb filament on the affected side. Consider replacing this sensor if troubleshooting suggests it's the culprit.

Step 4: Clean and Secure Connections

Clean the light socket and connectors to ensure a good connection. Corrosion or grease can impede electrical contact. Also, check that all pins within the connectors are secure and that there are no breaks in the wiring.

Step 5: Consider Other Electrical Issues

If the brake lights are intermittently failing, check the brake fluid level and the master cylinder cap. An incorrect fluid level or a faulty cap can trigger warning lights. Additionally, inspect the ignition switch for signs of wear or damage, as it can affect the tail lamp circuit.

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Further Troubleshooting

• If the brake lamp indicator is on but all lights function correctly, a grounding problem might exist. Aluminum body components can sometimes cause grounding issues.
• Replacing the gauge cluster or brake master cylinder cap, based on service bulletins, might resolve the issue if all else fails.

Conclusion

Fixing a brake light failure on your Acura RDX can be straightforward with the right approach. Always start with the simplest solutions—like bulb replacement and connection cleaning—before moving on to more complex diagnostics. Remember, safety should be your top priority. If you're uncomfortable performing any of these steps, seek professional assistance.

For more information on maintaining your Acura, consider reading related articles on our website:

• Understanding Acura NSX Years to Avoid
• Exploring Cars Similar to the Acura NSX
• Acura NSX Engine Swap Compatibility Chart

Nick Marchenko, PhD

Industrial Engineer & Automotive Content Specialist

Nick writes in-depth guides on car clubs, engine specs, vehicle ownership, and modifications, combining engineering knowledge with automotive passion.

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