Hi all:

I have been having a chronic issue with my left rear tail light, and I need your thoughts. This is for my '09 Flying Spur, but is applicable to all 05-12 Continental models.

The set-up: The rear tail lights use a variation of LEDs, called SMDs. The top "oval" has red SMDs and illuminates 50% at night and 100% when brakes are applied. The lower "oval" however, is used for BOTH nighttime driving AND doubles as the directional. These SMDs have TWO filaments within; one red and one orange. The RED filaments illuminate 50% at night and the amber filaments illuminate when the directional is ON. All of these SMDs are wired in "series" in groups of 4. They operate like christmas tree lights, in the way that if one burns out, the others become overloaded and eventually burn out as well.

When i got the car (pre-owned) about a year ago, a set of 4 of the directional SMDs in the left tail light were burned out, resulting in a warning light on the dash accompanied by a "hyperflashing" of the blinker. So I bought a used (but working) tail light for $250, and installed it. When first powered ON, in accessory, the blinker SMDs all worked. But once the engine was turned ON, within MINUTES, TWO sets of 4 SMDs started flickering and burned out!

So I assumed the car was giving too much voltage to the light itself. I took it to a Bentley mechanic, who determined that there was a normal range of voltage going to the light (between 12-13.2V)... So i now thought the problem must have been within the used light I bought.

So i bought ANOTHER used (but working) light. I installed it yesterday. When first powered on, with the engine ON, a set of 4 blinker SMDs (in a different location than those in the other light) immediately started flickering. I watched it for a few minutes. This same set of 4 would flicker and then remain ON for a few minutes, and then start flickering again. They're still acting this way.

Then I noticed that the RED filaments in these directional SMDs started to become affected. That entire oval of RED SMDs keeps going ON and OFF whenever I activate the directional.

Here are two videos that illustrate what I'm experiencing. The set of 4 orange SMDs (that are flickering intermittently) are working fine in these clips. The issue is with the RED SMDs in that lower left oval. And it's an illusion that the left light appears brighter than the right.



Any ideas as to what the heck could be going on?? I'm beyond frustrated. I am afraid that if I purchase a NEW light ($1500+ from the dealer) it will burn out just like the others. I called my dealer and they said it could be a number of things, and said the diagnostic fee could be hefty.

ANY and ALL input is appreciated!! Thanks!

-Chris

 

Hmmm, sounds like some type of electrical short yet you did test things. Do you have a meter that logs data, as maybe there's a short or some type of electrical gremlin giving momentary over voltage. A meter with log could give you a timeline of exactly what is happening electrically as am sure you agree it is hard to believe two light assemblies have the same problem.

These cars are sooo computer driven that who knows, it could be.... let's not think that. Don't even mention it! Ok, i'll say it could be a control module (gulp) and dare not ask what that may cost.

 

Damn I hope not. Hmm.. You got me thinking.

I went to look behind the light again. Look what I JUST noticed!! There's a white label attached to the cable going to the light, and it reads:

2008817053
LWA
3w5971019h
MOD 01
ISS 2
PASSED TEST
611 LHD RVC
date 17.11.08
Time 09:52





There also seems to be a brown wire being grounded directly to the battery beneath it. It goes to the same main wire bundle as the plug to the light.

The right side plug doesn't have this label.

Any ideas what this may mean?

 

No clue, wish I did.

 

Hello Chris,
Those are just the wiring harness labels, there are quite a few throughout the vehicle, I was wondering though by you stating "$250" for the tail light, is that complete with module each time, as I have not seen any in that price range unless they were smashed and or missing the module, a used module alone for the GT is $224 right now on EBay, although I now see that the FS uses a different setup than the GT as far as circuit board VS. module as far as I can tell, so were the two tail lights complete ?
Also the brown wires on each battery negative terminal is correct, but those are not the tail light grounds, on the GT I have the same brown wires to each negative post, but each tail light has it's own ground to the body via a ground stud, also the GT taillights do not function the same as a FS, see videos.

I will see what I can think the cause to be, top of my head is to check the grounds, more later.


Also I tried to call you but the 401 is NLIS.
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Ah! I never updated my phone number when I moved to FL from RI. I'll find where to update it.

Another update:

Last night I tried troubleshooting. I turned the directional ON, OFF, combinations with lights ON and OFF, etc. and then it did THIS: the left tail light and sidemarker ON by themselves!!! When ALL lights switched to OFF!


I couldn't get them to go out!!! I tried to unplug the plug to the tail light--Both went out. But when i plugged it back in, both the tail light and the sidemarker went on again. Unplugged and plugged back in, still wouldn't operate normally. After 20 minutes of switching a bunch of things ON and OFF, it somehow returned to normal operation. Now I'm just driving around unable to turn the directional ON out of fear that it might make the headlight and dome light turn on....

Where can I check for ground shorts? Any specific spots I should look? Thanks!!

 

....how did you finally resolve the crazy tail light thing...you have patience of Job...JimB

 

Hello,
I have a similar problem on a Flying Spur. Left taillight, only the flasher works for a short time correctly. After about ten seconds four of the Leds are flashing faster than the other ones.
Now I try to open the body, to come to the Leds, but it is not so simple as I thoght. I have removed the 4 screws from the backside and now the inner system I can move. But there is still the frontcover with the crome-ring and I think I have to remove this. All my attempts don't work.
Does anybody know, if it is glued to the black housing. If yes, in which way can I open it, without destroying the cover of the complete taillight.
Thank you in advance.

Greetings from fossi

please excuse my bad english, its not my native language.