The brake light fuse can blow out if it has a corroded circuit or melted terminals due to Increased resistance. Additionally, a short circuit can occur from poor wiring or defective switches leading to a blowout. Furthermore, brake lights that malfunction or overload can also cause a fuse to blow.
Are you experiencing a frustrating issue with your brake lights? If you’ve noticed that your brake light fuse keeps blowing, you might wonder what’s causing it.
So, today I’ll explain why the brake light fuse keeps blowing.
Now, let’s discuss why your car’s brake fuse keeps blowing in detail. First, I will explain what causes a fuse to blow. So, let’s get started.
Why Does the Brake Light Fuse Keep Blowing?
Generally, car fuses can blow out for a variety of reasons. Below are some of the most common reasons why brake light fuses keep blowing.
Reason 1: Corrosion In Fuse Circuit
The first reason is corrosion of parts in the fuse circuit. Over time, corrosion can build up on the contacts of a fuse, which can cause high resistance, resulting in a high amount of heat that can blow a fuse.
Solution: You need to clean the corrosion from the fuse circuit. Here’s how you can do it, follow the below step-by-step guide.
Tools Needed
- Rubber gloves
- Insulated tape
- Screwdriver
- Rust inhibitor spray
Step 1: Take Necessary Precautions
Wear rubber or plastic gloves to protect yourself and disconnect the negative cable of the battery to avoid any electrical hazards.
Step 2: Remove the Fuse/Fuses
Remove the fuse or the fuses you want to clean with a fuse puller. Some people face difficulties using the fuse puller as they don’t work sometimes, in that case you can use a needle nose plier.
Step 3: Clean the Fuses
Clean the connectors with a dry cloth or an electrical contact cleaner. Steel wool can also be used to scrub away corrosion buildup.
Remove debris away from the fuse holder, careful not to apply excessive pressure that could displace or damage the spring connectors. Once cleaned, inspect the connectors for any surface damage. If there is any damage, the connectors should be replaced.
Finally, put the fuses back to their place after cleaning and they should work fine now. Here’s a video you can watch Electrical Issues? Check & Clean The Fuses
Reason 2: Short Circuit
If a wire in a circuit comes into contact with a grounded surface, it can create a direct path for current to flow through. This can lead to a high current flowing through the circuit and blowing a fuse. Also, the brake pedal has a switch that electronically activates the brake light when you press the brake pedal.
If the switch is defective, it can draw more current to the circuit, blowing a fuse. Additionally, dual filament bulbs can develop a fault if their filaments short each other. Now, let’s move on to the diagnosis of identifying the short circuit.
Diagnosis: Short circuits in a vehicle’s electrical system are frequently found in the vehicle’s rear. First, to diagnose the issue, remove all the brake light bulbs, including the center light, and inspect the sockets.
Pay close attention to areas where the wires move, such as near the trunk lid hinge. Additionally, examine any additional trailer wiring connectors and disconnect them if present. After each component has been disconnected, test the system again.
Furthermore, a short circuit finder tool can simplify the process and prevent blowing additional fuses while diagnosing. Here’s a guide on testing a short circuit on your vehicle using a short circuit detector tool.
Tools Needed
- Short circuit detector tool
Once you have the tool, follow the below steps thoroughly.
Step 1: Connect the Detector Tool
Replace the fuse for the shorted circuit with a fuse adapter. Once the adapter is connected, connect the circuit breaker leads.
Step 2: Trace the circuit
Using a short circuit detector tool, trace the circuit by moving the probes along the wiring harness. Observe the needle on the tool as it moves back and forth. When it stops moving, it indicates you have located the short circuit.
Here’s a video to watch if the steps are confusing.
Also there’s a tool named automatic short finder, you can use that too. Here’s how.
Alternatively, if you don’t have access to a short circuit tool, there’s a DIY method to diagnose short circuits easily on your vehicle. Refer to the below step-by-step guide.
Step 1: Prepare a test light
Replace the blown fuse with a pair of spade terminals. Then, use short jumper wires to connect them to a 12-volt light bulb, such as a brake light bulb.
Step 2: Test the circuit
The bulb will be very bright and hot if the circuit is live and the short is present. So, be cautious when handling it or placing it near flammable materials.
Sep 3: Identify the source of the short
When the test light is on, unplug electrical connectors and move components around to determine which component caused the short. The bulb will dim or turn off when the short is no longer present. Continue to search for the source of the short until you find it.
Note:
To avoid the risk of electrical shock, it is recommended to use caution and seek the assistance of a professional mechanic if you are unsure or uncomfortable with locating and repairing a short circuit.
Solution: Inspect the sockets and connectors and replace them accordingly. Open the wiring harness and inspect the wires for any signs of wear or damage. Repair any damaged wires with electrical tape or replace if necessary. After the repair, reinstall the fuse and test the circuit to ensure it is functioning properly.
If you find that the brake pedal switch is causing the malfunction, replace it; here’s how to do it. Follow the below step-by-step guide.
- First, locate the brake light switch, which is usually located on the side of the brake pedal.
- Then, disconnect the battery to minimize the risk of electrical hazards.
- Remove the faulty switch, the switch may be held in place with a screw or a clip. Use a screwdriver or pliers to remove it.
- Disconnect the brake pedal switch wirings, it may be held with a plug or screws.
- Now, screw the wiring to the new switch and secure it with a clip or screw.
- Reconnect the battery and finally press the brake pedal to verify it’s working.
BY following the above steps, you can easily replace the brake light switch on your own. Remember, the brake light switch replacement procedure may vary from vehicle to vehicle. So, you refer to the user manual for more details or hire a mechanic. Meanwhile, watch this video tutorial How to change a brake light switch
Reason 3: Light Malfunction
The third reason is the light malfunction. If the brake light is faulty or has internal malfunctions, it can cause the fuse to blow. So, in this case, you need to replace the entire bulb and use the OEM one that the manufacturer recommends.
Diagnosis: Disconnect all rear tail lights, including the license plate light. Now put in a new fuse, reconnect and turn on the lights, check whether the fuse gets blown or not. If nothing happens, install 1 bulb at a time to inspect which light is causing the issue.
Solution: After identifying the faulty light, consider replacing it with a new one. Replacement procedure may vary depending on the vehicle type and model. You”ll find the detailed replacement guide on the vehicle’s service manual. For now, let’s look at the general replacement procedure of brake lights.
Tools Needed
- Flat screwdriver
- Philip screwdriver
- Access the tail light: On the inside of the trunk, remove the fasteners that secure the trunk lining to the tail lights. Then, pull back the trunk lining to access the tail light housing.
- Remove the bulb assembly: Twist the bulb assembly counter-clockwise to release it from the lens.
- Replace the bulb: Pull the old bulb out of the socket and insert the new one.
- Reinstall the bulb assembly: Twist the bulb assembly clockwise to secure it back into the tail light lens.
- Replace the trunk lining: Pull the trunk lining back into place and secure the fasteners to complete the replacement process.
Congratulations! You’ve successfully replaced the brake lights. Now you can test them whether they are working properly or not. Here’s a video you can watch for a visual guide.
Reason 4: Overload
During excessive electricity overflow, the fuse blows itself out to protect the component. If the wiring in the brake light circuit is damaged or frayed, it can cause the brake light to draw too much current, overloading the circuit and blowing a fuse.
Diagnosis: Locate the source of the overload by using a circuit tester or a multimeter to measure the voltage and current in the circuit. The source of the overload may not be immediately apparent, but tracing the wiring from the fuse to the components in the circuit should reveal it.
Note:
If you’re using an aftermarket version of the bulb instead of an OEM/OM one then it might be the cause of the overload. The aftermarket bulb may be incompatible with the circuit and can draw more current leading to a blown fuse.
Solution: If a component is found to be the source of the overload, it should be replaced. If the overload is still present after all components have been checked and replaced as necessary, the issue may be with the wiring itself.
Check for damaged or corroded wires and repair or replace them. Also, ensure you’re using the correct fuse amperage and OEM bulbs recommended by the manufacturer. If you cannot find the OEM part, find an interchangeable part with similar specs.
How to Locate the Brake Light Fuse On Your Vehicle?
Refer to the below table to locate the brake light fuse and find other details.
| Vehicle Models | Brake Light Fuse Location* | Fuse Identification Number | Fuse Amp Rating* |
| Toyota | Under the hood or the driver side’s footwell (varies with model) | User Manual (US)User Manual (UK) | 7.5A to 30A |
| Mk4 Golf | Watch Here | Fuse Number 13 | 10A |
| 2004 Jeep Grand Cherokee | Watch Here | Fuse Number 6 (F6) | 15A |
| 1998 Honda Accord | Watch Here | Fuse Number 10 | 10 A |
| Dodge Ram | Watch Here | F53, F82 | 20A |
| Ford F150 | Right-hand side of the passenger footwell behind a trim panel. | User Manual | 15A-20A |
| Subaru | It’s located under the instrument panel on the driver’s side. | User Manual | 20A |
| Jeep Wrangler | On the left side, under the hood | User Manual | 20A |
*Brake light fuse location and the fuse ampere rating may vary depending on the vehicle model years. Different models from the same generation may have different fuse requirements.
Blown Brake Light Fuse: What Are The Consequences?
Although having a blown-out brake fuel does not affect your vehicle performance, it significantly compromises your safety. If the brake lights are not working, it can make it difficult for other drivers to see when the vehicle is braking. As a result, it will increase the risk of a rear-end collision and unexpected accidents.
Can You Drive With a Blown Brake Light Fuse?
Yes, you can, but it’s highly discouraged. A blown-out brake fuse simply means that the brake lights won’t illuminate when you apply the brake. While it does not affect your braking and overall car performance, it dramatically reduces your safety on the road.
FAQs
Why Are My Brake Lights Not Working?
If your brake lights are not working, the bulb might have malfunctioned. If the bulbs are fine, the wiring might be a problem. Inspecting the wires for any visible signs of damage or corrosion. Finally, if the wiring looks okay, the fuse or the brake switch is the culprit. If you cannot diagnose the issue on your own, get help from a mechanic.
Do Brake Lights Have A Relay?
Some vehicles do have a brake light relay. It’s a switch that’s activated by the brake pedal, which sends power to the brake lights. Relays regulate the current flow to the tail lights to illuminate them. Refer to the vehicle’s owner manual or the diagram on the relay box cover to determine if your vehicle has a brake light relay and its location.
Does One Fuse Control Both Brake Lights?
Yes. In older vehicles, the tail lights and brake lights share the same fuse. However, newer vehicles may have separate fuses for these lights. In many vehicles, both lights are operated by a dual-filament bulb, but the circuits for each light are separate. As a result, if one circuit malfunctions, the other one can function without any issue.
The Bottom Line
That was everything about your query on brake light fuse keeps blowing. Hopefully, after reading this article, you understand why it happens and how to solve the issue. Always follow the user manual while replacing the fuse for the correct ampere rate.
Installing an incorrect fuse can blow out again and lead to severe component damage. That’s all for today. Thank you for your time. I’ll see you again, goodbye,
