Third brake light dim/not working
 

Hey everyone,

I usually check my third brake light in the rearview mirror when I'm driving, especially at night. On Saturday night when I was driving around, the third brake light (no spoiler) worked fine and lit up fully each time I checked. Then, on Sunday night, I looked in my rearview mirror and it looked like my brake light wasn't working anymore. At first I thought it was just the auto dimming mirror doing its thing but I turned my head back to look and I couldn't tell if it was working or not. I asked my friend to step on the brakes and drive up and down the street so I could see what was up with the brake light. The brake light would sometimes work, and sometimes would light up very dimly.

It doesn't seem like any of the LEDs are going out. The entire strip is lighting up dim. I'm thinking it's something up with the circuit? All of the LEDs in the tail lamps work fine. Just the third brake light.

I'm new to the car so I'm not sure what could be the problem. Any ideas or a fix? Should I get a new strip of LEDs or is that not the problem?

its a notorious problem wiht our Gs, about $300+ for the light replacement

Ouch! That's terrible. Is it generally an issue with the circuit/electrical system, or is it the LED strip itself?

Do you guys think it would be better just to get a trunk spoiler and use the brake light on that? Rather than replacing the high-mount brake light? I kinda wanted a spoiler anyways lol.

i'm currently experiencing this same issue with my sedan. I think we have the same problem. Do this:

Have a friend hold the brake pedal down ( or rig something if you don't have a buddy around).
If the light is dim, open the trunk and look for a wire hanging down from the rear deck lid. In the sedan it's pretty easy to tell which wire goes to the third brake light. Now gently wiggle the wire. Does the light go out or does it illuminate normally? If so you just have a loose connection to the LED strip. Take out the strip and see where the connection is going bad. Probably the solder joint from the wire to the LED board is starting to crack. Re-soldering the joint is way cheaper than a new unit. Free if you know how to solder or pretty cheap at any electronics repair shop.

The sedan is a pain in the butt to remove the light which is why mine is still broken. Haven't had time to fix it. I believe the coupes LED light can be removed from the inside of the cabin. Hope this helps.

Hmm I'll be sure to try that this weekend. Thanks for the tip!

Okay so here is what I mean by my brake light is coming up dim. Clearly all of the LEDs in the brake light and tail lights work. Only the brake light does this. Sometimes it lights normally and sometimes it does this.

I tried looking for the wire that goes to the brake light without taking apart anything but couldn't find it. Not sure what triggers this, as it only happens sometimes.

Attachment 264840

Okay here's a little update. I noticed that around the same time my brake light started doing this, the passenger side city light was out. I thought the bulb had just burned out at first, but on other occasions, they worked again. So it's definitely not a bad bulb. So I'm thinking the dim/dysfunctional brake light and the city light sometimes working and sometimes not is related. Seems like both either work at the same time or not work at the same time.

Is there a fuse or anything electrical that could lead to these simultaneously not working?

Did you get this resolved yet?
My high mount light doesn't work at all, but i just realized that I do have some fuse issues going on as well. (no power adapters right now, but I don't need them)
I have found the replacement bulb for $118 and it doesn't seem like it would be hard to replace. There is another thread here from several years ago with this same issue.
Amanda

using the VIN number I could tell you what the price on the whole assembly is, not 300...
I can get it for $175.00 shipped, but need the VIN to verify if that's the one or not....
just another option if you want to go replacement route
~Phil~

That's what I was thinking... I might have a fuse issue that needs attention. Definitely not the bulbs that are the problem since each LED still lights up. I'll look more into it when I have the chance over the weekend. Thanks for the tip though!

It most likely is the LEDs. They can go dim on their way to death. I have made a thread detailing how to replace these, and I offer to make replacements for people. However, if it goes to full brightness after wiggling the wire for it, then it is just a bad solder joint and can be repaired at least temporarily. I got a week out of doing that on mine.

https://g35driver.com/forums/lightin...ake-light.html

It's definitely not the LEDs. The all work fine, and I still can't figure out what's triggering them to stop working. When I backed out of my driveway on the way to the dealer to have them look at it, the brake light was not on at all. When I got to the dealership, it worked fine, and the guy told me that since it was working they "can't fix something that isn't broken" and proceeded to quote me $125 just to take a look at it. So I went on my own and took apart the trunk liner and wiggled around some wires hoping to see it flicker, but I got nothing. I banged around and wiggled wires and the brake light still stayed on constant.

I would have tried to remove the brake light housing to get to the assembly, but I have no idea how to do that or what else I can try. Can anyone point me in the right direction?

Yeah, sounds like bad solder. The sedan light is significantly harder to remove than the coupe's. I hear you have to take out almost all of the trunk lining to access the screws for it.

Hey guys, just noticed mine doing the exact same thing tonight. I used to be able to see my 3rd brake light reflection on my rear windshield (I have no spoiler). Went out to check and it lights up very very dim. Exactly as shown as in the picture that the93owner attached above.

The93owner, did you end up fixing it? Btw I drive an 06 coupe 5AT