Dim Tail Light

[mossman77]

The center LED tail lamp on my 04 G35 is not lighting to its full brightness. Sometimes it does, but most of the time it won't. Seems to be getting the correct voltage when the brake is applied, and I've removed the tail light and repaired what appeared to be a bad connection, retested the light (worked fine), then reinstalled it. Seemed to work well (full brightness) for a while, but now it's dim again. Any ideas? Faulty brake light switch?

[joe603]

I wonder if water is getting in there...check it again, and if you see corrosion then you'll need to clean the contacts and seal it up.

[james t kirk]

Bringing this thread back to life....

I have the exact same problem with my 05 G35. I noticed today that the centre brake light was very dim (though if you sort of squat down, you can see that it is working)

Noticed too that the LEDs tended to flicker. So the LEDs are working.

Off hand, I would say it was a bad connection, bad ground, or bad switch.

Believe it or not, I'm driving home after noticing this and right in front of me is another G35 and his centre brake light is not working at all.

Obviously there is a design problem here.

Wondering if anyone has any insight on this issue since this thread was posted about 3.5 years ago.

In reading the manual, it appears to be an insane job to remove the rear high mount stop light - requiring you to remove the rear parcel shelf finisher, which requires you to remove the seats, seat belts, rear pillar finisher, etc.

[04Orion]

Same issue on my 04 G35x. A friend driving behind me said it wasn't working at all, a few days later I had another friend come over to help investigate and it was working, first dimly when he pressed the brake, and then fine when I hit them. Since then, it works about 2/3s of the time (based on when I can see it, at night). Interested to see any other replies.

[james t kirk]

There must be a connection problem somewhere.

Looking at the wiring diagram, the centre brake light just comes right off the other brake lights, it is not a home run back to the brake light switch.

Tail lights work fine.

I'm surprised that this would not be a recall issue actually. Very surprised.

[splitkid]

Just noticed my light was extremely dim as well, you can barely see that it's turning on. The light is getting 12V and nothing on the circuit board is obviously wrong.

Have (and how did) you determine the problem? replace the stop lamp, brake switch, or what?

[james t kirk]

No,

Have not tried to correct problem yet. I've noticed that sometimes the 3'rd light works perfectly, other times, it's almost dark

Must be a connection problem somewhere, or bad ground.

[james t kirk]

Bringing this thread back from the grave, because I fixed the problem (myself).

All tire kickers on this forum, you can now click on "back" because you will be bored.

There were two problems associated with the dreaded "dim" centre brake light.

First off, the centre light would be dim, and I noticed that one of the LED bulbs was altogether dark. Strange. I thought LEDs were supposed to last forever, but no, that is not the case. In my driving around, I have noticed several G35s of my vintage (2005) that had dark or very dim centre lights.

The problem is obviously a design problem.

When I had my 2012 at the dealer to complain about its poop like responsiveness (transmission sucks) (another long story) I asked the friendly mechanic about my observation regarding my 2005 (the wife's car now) and the dim / dark centre brake light. His response was, "bring it in". Sigh. (I know that these guys know exactly what the problem was, but he didn't want to share the knowledge. Ok, buddy, don't ever ask me for a favour.)

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Anyhoo.

Problem No. 1 = dim centre brake light, one LED bulb dark.

Problem No. 2 = entire centre brake light dark.

Now to make it really interesting and odd, sometimes the damn thing would work perfectly. All LED bulbs glowing correctly. (When it was cold out - the centre brake light worked perfectly.)

Solution:

Problem No. 2 = bad ground. Solution = cut ground leading to centre brake light and attach to sheet metal on underside of rear deck. There are actually a couple of blank captured nuts on the deck (obviously this rear deck is used in more than the G).

Note, there are a few bad grounds on this car. The other one is the left reverse light. Also dark. Initially I suspected a burned out bulb, however, that was not the case. Test light showed no ground. Solution. Cut ground and splice into the other reverse light's ground wire.

Checked wiring diagram. Both the centre brake light and the left rear reverse light come off the same ground node behind the rear sail panel. No way I was taking that off. Followed the ground wires as far as I could till they disappeared, no evidence of any breakage.

Ok, so now left reverse light is illuminated again, but centre brake light is "dim" with one burned out LED.

F. I really thought that the bad ground was going to cure my problem. It did not. Though it did make a dark centre brake light dim again.

OK, so bite the bullet and take out LED strip.

Holy cow, what a job.

There are two philips screws which secure the plastic LED strip. The plastic assembly can be accessed from the trunk, but only on one side (right side). The left side, the screw is completely obscured by the sheet metal of the rear deck. The solution is to take out the rear deck, but that is a rather large job.

Plan B. Drill a 3/4" diameter access hole on the underside of the rear deck to get at the screw.

Now before you get all up in arms about cheating like that, the rear deck is FULL of holes for one thing or another. So drilling one access portal won't make any difference.

Drill hole, remove screw, remove LED strip.

Ah ha.

LED strip has 2 resistors and diode visible and god knows what else.

Solution = buy new LED strip from dealer.

Ouch - very expensive. $240.00 plus tax.

Plug in new LED strip.

Voila, it works.

Reassemble trunk interior.

Good to go.