A high mount brake light bulb is the bulb used in a car’s third brake light, the elevated light mounted higher on the rear of the vehicle. It enhances braking visibility for drivers behind you and is often required by safety regulations. Depending on the model, it may be a replaceable incandescent bulb or an LED module integrated into the housing.
Location and purpose
The high mount brake light (HMBL), sometimes called the third brake light, sits above the rear window or on the tailgate or trunk lid. Its elevated position helps motorists farther back notice when you’re braking, reducing the risk of rear-end collisions. In many countries, cars are required to have this extra brake light functioning properly for safety compliance.
Bulb types and replacement options
Vehicle configurations vary, so the type of bulb or module in a high mount brake light can differ widely across makes and models.
- Incandescent high-mount bulbs: In older vehicles, the third brake light uses a traditional 12-volt bulb with a replaceable base. The exact socket type (e.g., wedge- or bayonet-style) and bulb designation are listed in the owner's manual or on the bulb itself.
- LED high-mount lights: Many newer cars use an LED module or strip within the housing. These are often not user-replaceable as a single bulb; when an LED segment fails, the entire module or unit may need replacement.
- Hybrid or retrofit units: Some vehicles employ a combination of LEDs with a small incandescent bulb, or aftermarket upgrades. Replacement in these cases may involve specific assemblies or modules designed for that setup.
In practice, the right approach depends on your vehicle. If you see a clear LED array in the housing, you’re likely dealing with an LED module; if you see a traditional bulb socket, you probably have a replaceable incandescent bulb. Always confirm with the owner’s manual or a dealership parts catalog before purchasing.
Identifying the right bulb or module for your car
To identify the exact replacement part for your high mount brake light, follow these steps.
- Check the owner’s manual or the manufacturer’s parts catalog for the correct bulb type or part number for your vehicle’s high mount brake light.
- Inspect the third brake light housing: a visible LED array or strip usually indicates an LED module; a conventional bulb socket indicates a replaceable bulb.
- If needed, carefully remove the lens (and possibly the inner trim) to view the socket and base without damaging seals or wiring.
- Purchase the appropriate part—either the correct replaceable bulb with the matching base or the proper LED module/assembly specified for your car.
- Install securely, reseal any gaskets, and test the brake lights to confirm full operation.
With the correct part identified, installation tends to be straightforward, and you’ll restore visibility and compliance quickly.
Common configurations by vehicle era
As automotive technology evolved, so did high mount brake light design.
- Older vehicles (pre-2000s): Predominantly incandescent bulbs behind a removable lens; straightforward bulb replacement.
- Early to mid-2000s: A mix of incandescent and early LED modules; some units began integrating LEDs but remained serviceable in parts.
- Recent models (2020s and newer): Largely LED modules or strips integrated into a sealed unit; replacement often means swapping the entire housing or module rather than a single bulb.
Understanding your era and model helps determine whether you’ll need a simple bulb swap or a full housing replacement.
When to replace vs. upgrade
If one brake light segment fails, you may be tempted to replace only that bulb. For incandescent housings, a bulb swap may suffice. For LED modules, a single LED may not be replaceable, requiring a full module replacement. In some cases, upgrading to a newer LED unit can improve brightness and reliability, but it may also involve compatibility considerations with wiring and connectors.
Summary
The high mount brake light bulb sits in the vehicle’s third brake light, providing an extra level of visibility when braking. Depending on the vehicle, it may be a replaceable incandescent bulb or a non-replaceable LED module. Always verify the correct part for your make/model from the owner’s manual or dealer resources, and follow proper replacement steps to ensure safety and compliance on the road.
Do you need a high mount brake light?
With a high mount lamp assembly on every car, rear-end collisions become less common. Many different studies confirm that third brake lights reduce the likelihood of accidents. Since the introduction of high mount lamp assemblies on all cars, the US has seen: 200K fewer crashes every year.
What is a brake light bulb high mount?
Most newer vehicles are equipped with a high mount stop light, or third brake light, above the rear window on the back of the car. Third brake light bulbs shine a bright light that can alert drivers behind you when you hit your brakes, and lets them know if you are slowing or stopping.
Why are the brake lights not working on my Mitsubishi Outlander?
The most common reasons a Mitsubishi Outlander brake lights aren't working are a bad brake light bulb, blown brake light fuse, or a faulty brake pedal switch. Brake Light Bulb: A burnt-out brake light bulb can prevent the brake lights from illuminating, compromising safety and signaling to other drivers.
What does high mounted brake light mean?
High-mounted brake lights are brake signal lights installed at a higher position on a vehicle. When the driver presses the brake pedal, this light turns on to alert other vehicles to braking, thereby enhancing driving safety.