How to Fix Subaru WRX Brake Light Fail - A Complete Guide

By Nick Marchenko, PhD

When the brake lights on your Subaru WRX fail to illuminate, it's not just an inconvenience—it's a safety hazard. Fortunately, fixing this issue can often be a straightforward DIY project. Drawing upon collective wisdom from various enthusiasts, this guide will walk you through diagnosing and fixing common brake light issues in your Subaru WRX.

1. Check the Bulbs

It may seem obvious, but start by inspecting the brake light bulbs. Even if one appears to be working, it's worth checking all of them. Bulbs can fail simultaneously due to surges or simply because they share the same lifespan if installed around the same time. If you find any bulbs are burnt out, replace them with new ones. Remember, the brake lights in the WRX use separate filaments, so a bulb might still function as a tail light while the brake light filament is broken.

It's crucial to buy the proper bulbs for your Subaru WRX. If you are looking for replacement bulbs - check the chart below to find the bulb sizes for your car:

• 2019;
• 2018;
• 2017;
• 2016;
• 2015;

2. Inspect the Brake Light Switch

The brake light switch, located near the brake pedal, triggers your WRX's brake lights. If the switch is faulty or the connection is loose, your brake lights might not activate. Check the wires and ensure they're securely connected. Testing the switch with a multimeter can help determine if it's operational. If faulty, replacement is necessary.

3. Check the Fuses

A blown fuse can prevent your brake lights from working. Locate the fuse box in the left footwell and check fuse #16 (or the equivalent for your WRX model). If the fuse is blown, replace it with one of the same amperage. For detailed fuse assignments, refer to our Subaru WRX fuse box diagrams or maintenance guide.

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4. Examine the Wiring

Wiring issues, such as corrosion or damage, can interrupt the electrical connection to your brake lights. Pay special attention to areas prone to wear, such as wiring that passes through the hatch hinge in wagons. If you find damaged wiring, repairing or replacing the affected section is essential.

5. Consider the Brake Light Relay

If the above steps don't resolve the issue, the problem might lie with the brake light relay. This component is typically located in the engine compartment's fuse box. Testing or replacing the relay may restore functionality to your brake lights.

Throughout this guide, we've touched upon several potential issues that could lead to brake light failure in a Subaru WRX. For further reading and to enhance your understanding of maintaining your WRX, consider exploring related topics:

• Identification of the Subaru WRX Acceleration Hesitation Problem
• How to Prepare Subaru WRX for Off-Road
• Subaru WRX Years to Avoid
• What Causes Subaru WRX Vibration & How to Fix It
• Cars Like Subaru WRX
• Subaru WRX Engine Swap Compatibility Chart

By following these steps and consulting the provided resources, you can address common brake light issues in your Subaru WRX. Always prioritize safety by ensuring your vehicle's lighting is fully operational before driving.

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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