Reasons Why your Brake Lights Don’t Work When Headlights Are On

This is the coolest question of the day ‘What’s behind it if my brake lights don’t work when headlights are on?’ In this guide, we talk about the 5 reasons that occur problem in between brake light circuits. Driving at night is a good habit. Sometimes, it turns into a bad habit if we are moving our car with error brake lights! You need all the lights illuminated, including the headlights, taillights, and brake lights. If one of these lights is agitated, it may get you into danger. Plus, error brake lights can puzzle other drivers on the road. We rarely notice the backside and feel that the brake lights are not working. Indeed, someone should point you out about the error happening in the backside.

5 Reasons Why your Brake Lights Don’t Work When Headlights Are On

Brake Lights Don’t Work When Headlights Are On

I have experienced the same problem once I had a 1971 jeep. I replaced the vehicle’s old parts, including the wiring, light system, and pressure switch. After a few days, I was told that my brake lights don’t work if the headlights are on. However, my tail lights and directional work fine. It was a peculiar problem for me. I got the tail lights off if pressed the brakes during the ride. 

1. If the light bulbs are shattered!If the light bulbs are shattered!

The light bulbs are mostly blown out and responsible for the brake lights failure. I feel these bloomy lights as the most common reason. How to fix them? Remove the screws from the bulb’s conglomeration. You can go through the trunk and find the exact location. Push the bulb’s switch and turn them out from the socket counterclockwise. 

Mostly, you need to replace the bulbs if the bulbs are turned darkened, or you’ll see the filaments are blown. You will find the same bulbs from the market with the same features and wattage. Search them on Amazon if necessary. Some European cars have original specifications of the tail and brake lighting. Even though the European bulbs are structured with double filaments, you can replace them easily from a reliable store.

2. Sometimes, the fuse box and light switches are responsible

Secondly, the fuse box and light switch should be maintained. To get the options, you have to get the PDC (Power Distribution Center). The PDC is mostly located under the hood. Check the brake light switch off it if it touches the brake pedal arm and confuses the fuse box and light switch, including the brake lights. Remember that if the fuse box and the light switch are in any trouble, it will thoroughly affect the brake lights. We get a few enthusiasts, and they are facing their problems with a blown a fuse. You need to change them with a new one. The new lights should be equipped with the same amperage as the old unit. Do not let the fuse box to be a recurring problem! 

3. Check the Electrical Ground Check the Electrical Ground 

Here it comes with the Electrical Ground! Sometimes, the brake light switch is entirely functional. Then, you need to check for the electrical ground if they are good or bad. If wrong, then it might be happened due to a loose connection. Sometimes, the wires get departed, sometimes the wires have corrosion around it, and sometimes the wires are entirely damaged. You can give a try in case. Connect the light switch to a good (new) ground. Be mindful of testing it with a jumper wire. Then, press the brake pedal to ensure the brake lights on. Is it ON? Then, you’ve to replace or fix the ground connection.

4. Is the wiring system responsible for brake lights fail?

Besides checking the Electrical Ground, Be careful of studying the wiring! You should check all of the components we are talking about! It is necessary to ensure if they are working just fine. Okay, we value checking the wiring system. You may find the source of the problem here. The fuse panel that has gone through the brake light switch may be loose. Besides, if the regulator of the bulb sockets and lights are frayed, the bulb housing connection gets corroded. You are recommended to change these parts as soon as possible.  

5. At last, check the ‘Turn Signal Switch’At last, check the 'Turn Signal Switch

Our last talk is about inspecting the ‘Turn Signal Switch.’ We have been through many vehicle models, and our experience says that some vehicles are engineered between the brake light circuit and turn signal switch. For being that case, you get no response from the brake lights if they are damaged or bad. You can check the switch’s wiring diagram and find the connection between the brake light and turn signal. Access the turn light switches and find the brake light’s activation source to activate the light switch. Press the brake pedal and test the lights if they are on.


  • Why are my dash lights and tail lights not working?

You have to find the main source of controlling these lights. Maximum enthusiasts ask us about the head, dash, and taillights. Any of them can be failed or not working properly by the light circuit. You have to work on the disabled switches mandatorily.

  • Can I drive my car with no brake lights?

Indeed, the brake lights are not used for drivers’ safety but to indicate the passengers or ongoing vehicles about the safe run. You can drive your car without brake lights, although it is unfair or illegal in some states. 

  • Do brake lights have a fuse?

Yes! You’ll understand it very easily. Check the brake light switch. Is it good? Then, your lights are not illuminated due to the brake light fuse. 


In this guide, we have discussed the reasons that cause brake lights failure. You get your answer to the question ‘Brake Lights Don’t Work When Headlights Are On.’ Indeed, the headlights and taillights have separate wiring connections. It keeps one set of the headlights activated, whereas the other taillights don’t work! Your brake lights don’t get turned off without reason. You have to find the reason and work on it. Probably, you are afraid of the non-functional brake lights or taillights more than to fix! We recommend getting an expert mechanic to recover your vehicle shortly. Thanks for being with us!

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