Brake lights play an important role in keeping you safe on the road: they indicate to other drivers that you’re slowing down, preventing fender benders and serious accidents. So when your Subaru brake lights don’t light up, you need to act with a sense of urgency to find the cause of the problem and what you can do to fix it.
The primary reasons your Subaru brake lights won’t light up are; a blown brake light fuse, a faulty brake light switch, or a blown-out brake light bulb.
Let’s take an in-depth look at what could be stopping your Subaru brake lights from lighting up when you step on the brake pedal, how to address each cause, and how much you can expect to pay.
A Blown Brake Light Fuse
All modern cars have a fuse that protects the brake lights from a circuit overload. If this fuse blows, it breaks the brake light’s circuit, preventing them from lighting up.
Brake light fuses can blow for several reasons, but the most common culprits are the brake light bulbs. It’s common for these bulbs to corrode and their contacts to melt to the extent they touch. When this happens, it creates a short, causing the fuse to blow.
The fuse can also blow due to an electrical short in the filaments. This is common in Subarus and other cars with dual-purpose rear light bulbs that double up as brake and tail lights. These bulbs usually have two filaments. One is for the tail lights and is always on when driving, while the other is only activated when the brakes are engaged.
While dual-filament rear light bulbs are convenient in that they eliminate the need for separate brake and tail lights, they’re particularly prone to electrical shorts. Two filaments have a higher chance of shorting together and blowing a fuse.
The third bulb-related cause of a blown brake light fuse is a cracked rear light lens. Even a small crack is enough to let moisture into the lens and trigger a fuse-blowing short circuit.
Other reasons brake light fuses blow include faulty wires and ground or a malfunction in one of the many components of brake light circuitry.
How to Fix a Blown Fuse Brake Light Fuse
The first thing you need to do is to find out if the reason your Subaru brake lights won’t light up is indeed a blown fuse. You don’t want to go through the hassle of replacing the fuse, only to discover that it wasn’t the problem.
Start by locating the brake light fuse in your car’s power distribution center (AKA, the fuse box). The power distribution center should be under either the hood or the dashboard. If you’re having trouble finding it, consult Fuse Box Info’s Youtube video below. It shows the fuse box location and diagram for Subaru Foresters (SH; 2008-2012).
The fuse box location is pretty much the same as in other Subaru models, but you can always check your user manual just to be sure.
After locating the fuse box, use your car manual to find the brake light fuse and follow these steps:
- Turn on your Subaru’s ignition.
- Hook up a test light to a ground source (this can be your car’s dashboard or body).
- Connect the test light’s tip to both ends of the fuse.
- Gently press the gas pedal.
If the test lamp lights up after step 4, the fuse isn’t the problem. If the lamp doesn’t light up or only does so when you connect its tip to one end of the fuse, it’s time to shop for a new brake light fuse with the same amperage as the old one. The replacement will cost you $100-$150 (inclusive of labor), depending on your car model and who you hire to do it.
Be sure to test the new fuse before you leave the auto repair shop to make sure it’s working properly. You might also want to have the mechanic inspect your car’s circuitry, especially if your car’s brake light fuse has been blowing recurrently. More often than not, this is a sight of other serious electrical problems in the system.
A Faulty Brake Light Switch
The brake light switch is responsible for turning on your brake lights when you hit the brakes. If it’s faulty, out of position, or otherwise compromised, your car’s brake lights won’t light when braking. This goes for all car brands, including Subaru.
Brake light switch issues have been particularly rampant in Subarus in recent years, so much so that they prompted a recall of about 1,303,530 vehicles for brake light switch replacement.
Here’s a table showing the specific models affected by this recall:
| Model | Manufacturing Period Subject to Recall |
| Crosstrek | May 17, 2010 – June 13, 2017. |
| Forester | December 18, 2010 – April 28,2016. |
| Impreza 4-door models | April 26, 2007 – October 28, 2016. |
| Impreza 5-door models | April 28, 2007 – October 3, 2016. |
| WRX 4-door models | April 26, 2007 – January 15, 2014. |
How to Fix a Bad Brake Light Switch
First off, determine whether your car was subject to the recall described above. If it was, chances are you missed an email from Subaru informing you of the issue. Just get in touch with them and see if you can have the switch replaced for free. It only takes an hour or so.
If your model isn’t subject to the recall, you’ll need to do a bit of troubleshooting to determine whether the switch is indeed what’s stopping the brake lights from illuminating.
Here are a few signs to look out for:
- If your car is automatic, it won’t shift out of Park even if you take your foot off the brake pedal.
- Stability control and anti-lock braking issues.
- If you own one of the newer Subaru models with EyeSight® Driver Assist Technology and a push-button starter, these features may not work.
If it turns out that your brake light switch is faulty, you’ll need to replace it on your own. Here’s a
Youtube video to walk you through the process:
Of course, you can always hire someone to do it for you. If you need help finding a mechanic, check out our guide on what to look for when choosing a Subaru mechanic.
Expect to spend anywhere between $60 and $250, depending on your car model and who you hire to do the replacement (if you choose not to DIY).
Blown-Out Brake Light Bulbs
If one of the brake lights won’t light up and the other one is working fine, the former’s bulb is likely blown out. It’s not common for both brake light bulbs to blow out at the same time unless you’ve neglected them for a long time.
How to Fix Blown-Out Brake Light Bulbs
Start by inspecting the affected bulb for blown filaments or dark spots. If you don’t notice any of these signs and still suspect the bulb is blown, remove the entire rear light and test the bulb with any external 12-volt power source.
Once you’re sure the issue is a blown bulb, purchase a new bulb for about $5 to $10 (the price may be higher depending on the bulb design) and install it per the instructions in the Youtube video below. It covers brake light replacement for a Subaru Outback, but the steps are virtually identical for other models.
Final Thoughts
It’s worth noting that this article focused on the primary reasons Subaru brake lights fail to illuminate. There are other less-common causes, like wiring issues, but these are almost impossible to troubleshoot without expert help because car lighting circuits can be difficult to navigate for the average person.
So if your brake lights still don’t light up after trying the fixes we’ve discussed, you should bring your car to a Subaru expert. If you are in the Little Rock, Arkansas area, give us a call today!
