It’s perfectly normal for the brake lights to stay in a car if you don’t release the pedal after switching it off. The lights should turn off as soon as you let go with your foot and leave your vehicle.
But what if the brake lights are stuck on after you let go of the pedal? And even after you leave and lock your car?
That’s another thing altogether.
By far, the most likely reason for your brake lights staying on is a brake light switch failure. The simplest option is to have a mechanic install a new one.
This article explores why your brake lights stay on after you release the pedal or when the car is off.
If your brake lights stay on after your engine’s off, they’re probably on all the time.
Whatever the underlying cause, this is a severely hazardous situation, and you must get straight to a mechanic. Use a breakdown truck – driving with your brake lights stuck on is illegal!
Let’s start with the basics.
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How Do The Brake Lights Work?
Before going through some potential reasons for your brake lights staying on, it’s crucial to know how they work. For more information on how the brakes work, check out this article on Auto Chimps.
When you depress the brake pedal, a switch closes and completes the circuit to the lights. Conveniently, this is known as a brake light switch.
Electricity can then flow to the three brake lights at the rear of your car (one on either side and one on the top).
When you release the pedal, a spring pushes it back to its resting position, and the switch opens. This cuts off the current and means the lights turn off.
The brake light switch should close as soon as you press the pedal. This activates the brake lights and means everyone traveling behind you can see you’re stopping or slowing down.
Why Do My Brake Lights Stay On?
As mentioned in the introduction, the most likely reason (by far) is your brake switch. However, there are a couple of other possibilities.
Brake Light Switch Failure
When the brake lights stay on after you turn the car off, you should immediately look at the brake light switch. It might be referred to by several other names, including:
- Brake switch
- Brake pedal switch
- Brake light sensor
The brake light switch should be open when you aren’t pressing the pedal. This disrupts the circuit and means there’s no current flowing. When you press the pedal, the switch should close.
The brake light switch can fail. This can happen due to the following:
- General wear (most common)
- Significant impacts
If the switch becomes stuck in the closed position, it’s always drawing current from the battery. Over time, this could drain it and make starting difficult.
Note: it could also get stuck in the open position. In this case, your brake lights wouldn’t come on when you press the pedal. This is just as hazardous, if not more so.
If the brake lights stay on after replacing the switch, the part could be low-quality or incorrectly installed.
Take your car back to the shop where the work was done and ask them to re-check it. There could be other problems at play, too, don’t forget.
How To Fix The Brake Light Switch
The fix? Simple. You need a new brake light switch.
It’s likely to cost you between $120 to $150.
Have an OEM component installed by a reputable mechanic that you trust. Before your car’s released back onto the road, they should check that everything’s in order.
Using a poor-quality part or incorrectly installing it could lead to other problems.
Brake Pedal Not Returning To Rest Position
After you release the brake pedal, a spring mechanism pushes it back to its resting position against the stopper.
Over time, this spring mechanism will wear out. You might find that the pedal isn’t traveling all the way back to its typical position.
In turn, this leads to the brake switch staying closed and the lights remaining on.
The brake pedal should feel noticeably different and quite sluggish. Have it checked out as soon as possible. If it’s been happening for some time, you might have gotten used to it.
The stopper could also have come off or otherwise been damaged. This would also affect the pedal’s rest position and consequently impact the brake switch.
Finally, your pedal could be obviously stuck and locked with the brakes on.
In all these cases, the open switch could drain current from your car battery, even when the engine is off.
How To Fix It
The best way to fix your brake pedal not returning to the rest position is to have it inspected. Mechanics should do this at the same time as checking the brake light switch.
They’ll check the spring and the stopper. Both should be clearly visible without the need to remove any panels.
You’ll pay next to nothing in terms of parts. You shouldn’t expect the cost to exceed $40 for this type of work.
That said, getting the right part might take a little while. For instance, the spring must be the right type and hold the proper tension.
Of course, if your brakes are stuck on, there could be a more serious underlying issue. Expect to pay significantly more.
The term “electrical fault” encompasses an almost innumerable range of possible problems.
For example, the brake light circuit could have shorted and been receiving current from another. The ECU might be malfunctioning to a severe extent.
Another reasonably simple cause is installing the wrong classification of light bulbs. Many cars come with light bulbs with two filaments and two distinct circuits. This means you can see the same ones for the brake and taillights.
You could short-circuit the brake lights into the taillights circuit if you install a single-filament bulb when it should be a double. This would mean they’re always turned on.
Always install the right light bulbs! You’ll find all the information you need in your owner’s manual.
How To Fix An Electrical Fault
An electrical fault should be diagnosed by a specialist auto electrician. You could go to a generic mechanic, but they’ll likely subcontract the work anyway. Avoid the markup by going straight to the experts.
You should only take your car to see them once you’ve ruled out the above. That’s because it’ll be expensive – well into the hundreds and possibly breaching the $1,000 mark.
Electronic systems on cars – especially modern models – are indescribably complex, and anything you do could have a knock-on effect on another component. You could also endanger yourself. Don’t try fixing an electrical fault unless you know what you’re doing.
Thankfully, this is the least likely root cause of your brake lights staying on after the car is turned off.
Can I Fix This Problem Myself?
It’s always the safest bet to take your car to a mechanic. That’s especially true if you have no mechanical experience or know-how.
Don’t take chances with the braking system. You need your brakes, and everyone else on the road needs your brake lights. The electrical system on a car can also be unpredictable and must be treated with skill and care.
Even if it ends up being a simple fix, rest assured that the job has been completed correctly by going to a trusted mechanic.
In most cases, fixing your always-on brake lights shouldn’t be too expensive or take too long. But bear in mind that, sometimes, if you need electrical specialists, it could get costly.