Rear light unit not ok

After turning ignition switch the rear light did not illuminate.
Front light however did.
After several attempts with the switch it worked but stopped when using brake.

measured 12volt in the plug for braking and normal light.
It seems that my rear led light is on its way to GRiSO heaven.

Pulled on the wiring but no light. Cleaned the plug no result.
Can't find anything that is related to my kind of issue.
Seems like this does not happen verry often.

Sombody a suggestion?

New rear light costs 130 euro grrrr

Yup, it sounds like it's gone and deaded itself. Being an LED light I imagine there is a transformer in it somewhere to step down the voltage. Chances are that has shat the bed. As you say, failures are rare, I think I've seen two since 2005, on Grisos at least. They do come up on fleabay from time to time but given how reliable they generally are perhaps it would be best to just buy one while they are still available and hope that it remains sound.

The bulbs were all incandescent originally.  The headlight was pathetic, so it was first to be replaced -I fitted an OSRAM 7" Round Black Led Headlight (105W).

Tail light is normally second to gain attention.  It too was an incandescent duel filament bulb, which is usually replaced with a dual LED setup.

But losing both tail-lights at once is not common.  Perhaps the common return wire has lost contact with the frame or battery negative.  Simple check with a short piece of wire will determine if it has.

Pete Roper wrote:

Yup, it sounds like it's gone and deaded itself. Being an LED light I imagine there is a transformer in it somewhere to step down the voltage

Sorry Pete, but transformers do not work in a direct current environment.

Cool. That's why I leave it up to clever people to answer technical electrical questions as a rule

Will visit TLM today. Maybe they want to test the taillight. If failed, ill buy a new one.
Sometimes the light will illuminate. After hitting the brake all fall out.

Taillight start working . The mighty GRiSO repaired itself.
Think the electrical spray did it´s job.  
(though i think the complaint will occur soon)

Deepdive wrote:

Taillight start working . The mighty GRiSO repaired itself.
Think the electrical spray did it´s job.  
(though i think the complaint will occur soon)

This points to Kiwi-Dave's point about the "common return" or earth/ground wire.

If more than one electrical component is jointly wired in a plastic insulated box (like the rear light unit)
then a poor or intermittent earth/ground connection for the whole unit means that one component may reach earth through the other component.
so you get apparently weird effects

Check the earth return - blue wire

Indeed, Kiwi was right.
The reason why i checked again this morning.
Thanks ghetto.

Pete Roper wrote:

perhaps it would be best to just buy one while they are still available

Took that to heart and ordered one for the shelf

Complaint was intermittent. So bought new from TLM.
Solved the issue.
Seems like the taillight can be opened. Assume nobody ever did, cause normaly there´s no issue with the taillight´s of GRiSO[You must be registered and logged in to see this image.]
.

Deepdive wrote:

Complaint was intermittent. So bought new from TLM.
Solved the issue.
Seems like the taillight can be opened. Assume nobody ever did, cause normaly there´s no issue with the taillight´s of GRiSO[You must be registered and logged in to see this image.]
.

I recently faced with the same issue as well, wanted to take out the unit and check if connections are welded in. How does one open up the rear light unit ?

The tail light unit is a bit of a pain to take apart as the flat cover on the back is held on with glue/mastic but a heat gun will work. all the LEDs are surface mount and in my case it was moisture that keeps on breaking the LEDs.

Need to try and split it again but I used CT-1 last time

In the Nissan 350Z scene they make use of an oven. Google on it. The gleu will be softened and therefore easier top open with a bit of force and tools. Is youtube the best friend again?

LEDs are simple devices and the current through them is limited by resistors so as not to exceed the rated current for the particular LED. Often the LEDs are strung in series, still with a current limiting resistor.

There may be a broken track on your tail light circuit board. These are often extremely hard to see but easy to repair. If you have someone that is good with electronics, they may be able to repair it as a spare.

Dear all, just opened my taillight, since LEDs shine only very slightly (about 5%). I do not see any obvious problem, what can I do? There is no spare Taillight on offer in Europe…

Have you checked the +12V and ground connections are OK?

Does the brightness increase when you apply the brake?

Yes, both connections okay and brightness does increase using brake - it is “just” that it is missing 95% of brightness overall…

Hmm. Possibly a dry joint, or a resistor that's gone high (unlikely). I will need to examine the circuit board and run some tests before commenting further. I should have an opportunity to do that on Wednesday or Thursday.

I agree to this assessment! Would be happy to hear

A closer look at the tail light assembly gives me pause to attempt to separate the lens from the base. I fear it is too fragile to separate without damaging it.

Definitely a horrible job! I will take mine to a circuit board specialist… I haven’t seen the tail light available as a spare part anywhere in Europe!

I think your only option will be repair, or purchase from a dismantler/wrecker.

For the record: Took it to a circuit board specialist, ground cable was replaced and all resistors resoldered. Back to working…
So: hardest part is to separate the glass from the frame, rest is routine (for a specialist).