4runner Brake Light Not Working (Causes And Fixes)

Your Toyota 4runner brake light not working is a troublesome experience that can comprise your road safety and even lead to violation of traffic regulations. But worry not. We’re here to help you troubleshoot and resolve this problem.

4runner brake lights not working can be caused by several factors, including faulty brake light switch, burned-out bulbs, blown fuse, bad relay, wiring issues, and grounding issues.

In this article, we will delve into more in-depth details about this Toyota 4 runner problem. We’ll discuss all the common causes behind your car’s malfunctioning brake light and guide you toward a potential solution for this issue.

4runner Brake Light Not Working Causes:

Here are the most common causes behind your 4runner brake light failing to come on:

Faulty brake light switch

A failing brake light switch is probably the most common reason behind your Toyota 4runner brake light not working. If both your brake lights don’t come on when you brake, you’re most probably dealing with a faulty switch.

When you depress your car brake pedal, you simply complete the brake light switch circuit. However, if this switch is damaged or is pushed out/misadjusted, it is unable to complete the circuit—causing all the brake lights to stop working.

Burned out bulb

If you have a situation where only one brake light is malfunctioning, then it is likely a blown bulb causing the issue.

When the filament inside the bulb breaks, it’s unable to illuminate the gas inside when the brakes are applied.

A blown bulb doesn’t interfere with the rest of the brake light system, so the other brake light bulb should continue functioning normally.

Blown fuse

Another reason the two brake lights could be failing to illuminate when the brakes are applied is a blown fuse. The fuse that controls the brake light is usually located in the fuse box. Once you get to this fuse, you can simply pull it out and inspect if the wire inside looks broken.

Bad relay

The work of a relay is transferring electrical power from the battery to your brake lights. However, if the relay fails, the connection isn’t completed, and this makes the brake light stop working.

A relay may malfunction due to bad grounding; poor grounding means the circuit isn’t protected and doesn’t have an outlet for excessive charge buildup. A bad relay cannot successfully power your lights.

Bad socket

An issue with the bulb socket can also make one brake light stop malfunctioning. Potential socket issues include a pushed pin, corrosion, or problems with the wire crimps at the socket.

The socket plug ears particularly tend to easily bend flat, especially if inserted in the wrong manner. In this case, you should remove the socket and bend up these contacts so they stand proudly off the base.

Wiring issues

If your brake lights are malfunctioning, then the wiring that runs from the brake switch to the bulbs could be another potential cause. The wires could be damaged, frayed, cut, short, or even have poor grounding.

All these wiring faults can disrupt electrical power flow to the brake lights, making them stop illuminating on pressing the brake pedal.

Grounding issues

If there’s a ground wire that runs to your brake light switch, then you may want to check whether it’s corrosion-free and tightly secured

If you’re unable to locate the ground wire, try running the jumping wire to stand in for the ground wire. Then, go ahead and test the brake light switch. If it works fine, then you should fix the ground wire.

What To Do If Your 4runner Brake Light Is Not Working

If your 4runner brake light is failing, there are a few steps you can take to troubleshoot this issue and even fix it to restore the stop light functionality.

Here are the troubleshooting tips for this issue:

• Check the bulb. Get it out of its socket and inspect if it has darkened or has a broken filament inside.
• If the bulb looks alight, look for evidence of moisture (condensation) rust, or stains on the contacts. If they look dirty or wet, clean them using good WD-40.
• Try jiggling the wires. If this makes the light go on and off intermittently, this is a sign of a bad connection in the harness.
• Check the fuse for brake lights under the bulb. You can inspect it visually or by using a multimeter to test for continuity. If the fuse is blown, simply replace it with a new one that has the same rating.
• Inspect the sockets for damages and corrosion. If you notice any signs of rust, remove the socket and clean the contacts for better conductivity.
• If necessary, pull the contacts up a little bit to add springiness to them and enable them to create a better connection with each other when installed.
• Next, you should test the brake light switch. Use a multimeter to test the switch continuity when pressed. If there’s no continuity, the switch is faulty and needs to be replaced.
• Examine your car wiring for signs of damage, loose wires, fraying, wear, etc. Look out for any damaged or corroded connections that may interrupt electricity flow. Repair/replace any faulty wiring as necessary.

If the above tips don’t yield any helpful solution to your brake light problem, then you should consult a qualified auto technician or dealership for further assistance.

Your car may be facing complex electrical issues that the professional has the expertise and tools to accurately diagnose and repair.

Why 4runner Driver Side Brake Light Is Not Working

If your 4runner driver side brake light is not working, then there are several potential problems to consider.

Since the other brake light is functioning correctly, you should rule out a blown fuse or faulty brake light switch as the potential cause behind this problem.

One likely culprit would be a burned-out bulb. Inspect the bulb. If it looks burned out, replace it with a new one and see if the issue goes away.

If changing the bulb doesn’t work, your brake light could be having an issue with the socket. Corrosion, water ingress, pushed pins, wire crimps at the socket, or bad sockets can prevent the brake light from forming proper contact, thus restricting proper flow of power.

Inspect the socket for signs of damage/corrosion and repair or replace it as necessary. Be sure to inspect and clean all the contacts.

Also, check that the bulb socket’s contacts that mate with contacts in the brake light housing aren’t smashed flat or corroded. Get the socket out and clean these contacts. Pull them up a bit so they can make better contact when you put the socket back.

You can check more helpful information on this forum thread from other 4runner owners discussing this exact issue.

Here’s a video on how to fix the connectors:

Video:

Why Does The 4runner Brake Light Come On And Then Go Back Off?

Your 4runner brake light may also come on and then go back off. There are several potential causes to consider if faced with this intermittent brake light behavior.

One such cause is a loose or faulty connection. Examine the wiring and connection related to your brake light system. Ensure there are no loose connections that could cause intermittent behavior. Ensure all wiring harnesses are secure and free from damage and corrosion.

If the bulb itself isn’t properly seated in its socket, or the socket is faulty, it may also result in intermittent connection. Remove the bulb and inspect it as well as the socket for signs of corrosion or damage. Clean the contacts if necessary and ensure the bulb sits in the socket properly.

Sometimes, the brake light switch may intermittently fail to activate/deactivate the brake light, leading to this odd brake light behavior. Inspect the switch and adjust or replace it as necessary.

Electrical issues such as short circuits, poor grounding, faulty relay, etc., may also make the brake light keep coming on and off. Since electrical issues may be complex to diagnose, we advise you to let your mechanic do it for you.

Where is the Toyota 4runner brake light fuse?

The brake light fuse in Toyota 4Runner is usually located inside the fuse box. The box itself sits in the engine compartment or in the interior cabin on the driver’s side.

The location varies depending on your 4Runner trim level and model.

For the fuse box located in the engine compartment, the box usually sits near the car battery or along the fender wall.

For the box inside the cabin, the location is beneath the dash or in the kick panel lying adjacent to the door on the driver’s side.

The lid for the fuse box usually has a diagram that shows you the fuse layout. It provides you with alphabetical or numerical designations of different fuses, including the brake light fuse.

Why does your 4runner tail light work but not my brake light?

If your 4runner tail light is working but the brake light is off, there are several likely causes behind the problem.

A burned-out bulb is one potential cause. Since brake light and tail light operate on different bulbs in most car models, a blown brake light will not affect the tail light functionality.

A defective socket or assembly can also prevent the bulb from receiving power or making proper contact, affecting the brake light.

Wiring issues such as loose, worn, or disconnected wiring can also disrupt the electrical power flow and make the brake light non-functional.

Sometimes the fuse responsible for activating the brake light may get faulty, resulting in the brake lights not functioning.

If you’re experiencing issues with your 4Runner’s brake light not working, it’s important to address the problem for safety reasons. However, if you’re also encountering similar problems with your Jeep Wrangler’s third brake light, you may find our article on Jeep Wrangler third brake light not working helpful. Additionally, if your brake lights are not working but the third brake light is still functional, you can refer to our article on brake lights not working but third light is for possible causes and solutions.

FAQs:

Conclusion

Your 4runner brake light not functioning can be attributed to several causes. The most common causes include a blown bulb, failing brake light switch, wiring problems, blown fuse, or even grounding problems. Since the brake light is a crucial safety feature in your car, we advise you to diagnose and fix the underlying problem as soon as possible.

Follow our troubleshooting guide above to help you find the exact cause behind this brake light problem. However, if you’re unable to fix the problem your car is facing, we advise you to take your car to the dealership or qualified auto mechanic for help with diagnosing and fixing the issue.