I have a 2007 Honda Accord. A few days ago I backed the car up to the front of the house, and in the reflection of the windows and glass I noticed my brake lights were very dim looking. The brake lights on this model/year are LED brake lights that are Honda genuine brake lights. After I noticed, I put the car in park and tapped the brake lights several times and noticed they got very bright, then very dim. Then bright, and dim again and so on and so forth. They also flickered on and off at one point while my foot was planted firmly on the brake pedal. Is this a popular known issue with these brake lights? What can I do to correct this? Took the car back to the dealership and they said there was nothing wrong. (Of course)
It is possible that your alternator is giving you the first hint that it is beginning to fail.
I strongly suggest that you have a different mechanic check the alternator’s output before you wind up stranded somewhere.
I would suspect the brake light switch (sometimes called the stop light switch) that is mounted on the brake pedal. They get flakey sometimes and are cheap to replace.
If you tapped on the tail lights and the brightness changed then there’s a problem with LED arrays. The LED array comprises of the LED’s with resistors into the LED array and resistors between the LED’s.
Try looking for poor connections at the plugs for the LED arrays. Otherwise there’s something wrong with the LED arrays.
Good idea to put solid state circuit boards with LED’s and resistors where you slam a trunk lid.
Thanks for your comments. The resistors sounds like the problem. The car only has 60,000 miles on it and it’s a Honda so I doubt that the alternator is the issue. I do believe its something with the wires, or a loose connection somewhere internally. I’ll double check the brake light switch, but because the brake lights do illuminate and have never failed to do so, that may not be the problem. I appreciate the comments. This car is paid off and in excellent condition so I plan on getting another 100,000 out of it!
Repeat you test, but this time do it once with the headlights/taillights off and again with the headlights/taillights on. If the test with the headlights/taillights on results in the taillights going off or flickering when the brake is pressed, then you have a ground issue. Start looking for the ground wire.
BTW, is the cyclops (center brake light) doing the same thing?
Keith- You hit the nail right on the head. I forgot to mention that it does it mainly at night when the headlights are on. I have recorded a quick video hopefully I can post it on here. Notice in the video, when I press the brake lights, and my foot is planted firmly on the brake, the brake lights (yes the center one as well) go from dim to bright on their own. I also turned the lights on and off a few times to see if that made a difference. I would just like to say that these comments are all greatly appreciated. I rely heavily on my car and taking care of it is a top priority for me. Video to follow.
I probably won’t be able to view your video, my internet connection is horribly slow, about 120kbps at best. But do you notice the headlights dimming as well? LED’s draw very little current, but they are very voltage sensitive. One common problem for voltage variations in the chassis is the engine to body ground, but that usually shows up as a slight flickering in the headlights as well.
One more thing, It could also be as simple as a loose connection at the battery or corrosion on the battery terminals. LEDs are very voltage sensitive and it would take much. If you haven’t cleaned and tightened your battery terminals in a while, it wouldn’t hurt to do it now, just to see.
One more possibility is that the brake light switch at the pedal, which is what actually grounds the circuit, has worked its way out of adjustment or become corroded inside somehow. A poor contact can act like a resistor in the circuit, intermittantly dropping the voltage available to the lights.
Keith- I wasn’t able to upload the video, something about the size being too large. My guess is because of the digital camera I used. But, no the headlights aren’t dimming at all. The battery was tested by my mechanic the last oil change I had, and it checked out ok. There is no corrosion on any of the battery or on the terminals. Im convinced its a short somewhere in a wire that is causing it. Also, I was rear ended pretty badly a few years ago and the trunk lid and tail lights were replaced. I think that could also be the problem. The wires may not have been connected properly or may just be loose and/or after market. (I hate anything and everything after market) I checked almost every fuse and they all seemed to be fine. I figured if it was a fuse, the tail lights wouldn’t work at all if the fuse was bad. I’m open to any other suggestions, sounds like you know your stuff. @ The same mountain bike- Thanks. I checked that, doesn’t seem to be the problem. That switch works just fine. The car has been garaged since 07. This is just a weird thing that my car does, just my luck I guess. I’ll keep trying other things but the brake lights work enough for people to know I’m stopping.
Sometimes as you put a bag of groceries in the truck, you’ll accidentally knock the brake light assembly, which can loosen the connections. I had this very thing happen w/my Corolla, and all I had to do was tighten the connections. Suggest to check the wiring in the trunk going to the light assemblies for anything clearly wrong before embarking on more expensive possibilities.
Also, make sure the lights are actually dimming. Have someone touch the brake pedal on and off while you are actually in back of the car looking. It may just be some sort of optical illusion in the reflection.
"I put the car in park and tapped the brake lights several times and noticed they got very bright, then very dim. Then bright, and dim again and so on and so forth. They also flickered on and off at one point while my foot was planted firmly on the brake pedal."
By chance, are these the brake lights that flash brightly when first hit? You see them a lot on motorcycles and work trucks.
Not sure whether Honda sticks those lights in but you can buy them with that option built in. It is a safety feature, them being very bright when they first turn on so it can very easily be seen by anyone in the back of you.
Have someone press your brake while you watch it.
An accident eh? That presents another issue, water. Many times the body shop can’t completely seal up a car after an accident and water gets into places it shouldn’t. And one of those places could be the cavity where the connector sits. Water gets into the connector and the conduction becomes intermittent.
Honda uses a redundant ground system. a ground wire loops through all your taillights and center brake light and anything else electrical and is connected to the body at two points, one on each side of the car. They don’t normally have a ground problem, but after an accident, it could have one. One or both ground connections could be loose or corroded from the water getting in.
I don’t have access to all data at my house, but some people who visit here do. Maybe one of them will look up the wiring harness diagrams and tell you exactly where the ground lugs are located. If your car were ten years older, I could help, but I don’t have the FSM (factory service manual) for your generation Accord.
I would not rule out the fuse too quickly, sometimes they can have a bad connection on the blades. The fuse is good, it just needs to be pulled out and reinserted to refresh the connection. The fuse is probably the only place where the wiring for all the brake lights come together so if all the brake lights are dimming in sync, it could be the fuse or the ground. It won’t be the individual brake lights.
Thanks every one. The issue is getting worse, going to check the fuse again and maybe replace it just to see if that fixes it. The car is actually still under warranty so I can take it to the dealership, but unfortunately my local Honda dealership is full of snobs and I don’t like to take it there. The other Honda dealership is 45 minutes away. Thanks for the comments. I’m going to keep trying!
Greg, I was just checking the service manual for my 97 Accord. It may not apply exactly the same in a 2007, but manufacturers tend to not change anything they don’t have to because of tooling and training costs.
In the 97, the brakes and horn are on the same fuse in the underhood fuse box. If you find this fuse and it is labeled brake/horn, then just blow the horn and see if it is steady or if it also fluctuates. If it is steady, then hold down the brakes and see if the lights go steady when the horn is blown. If the horn fluctuates or if the lights go steady when the horn is blown, then the issue is between the fuse and the battery.
If the horn has no effect and is steady, then it has to be the brake light switch/connections or the ground. Check your owners manual and see if the door ajar icon includes the brake light warning like it does in the 97. The icon in the 97 is the shape of the car and a red door shows if the door is open. If a tail light lights up on this icon, it means the bulb has burned out. It does not monitor the center light. See if the tail light flickers on the door ajar icon on the dash. If both indicator lights flicker, it is definitely at the ground points in the rear.