Repair of LED tail light cluster

[xantia_v6]

My Peugeot 308 CC has failed it's WOF (MOT) test due to some of the LEDs in a tail light not working. It looks like about 25% are not lighting.

I imagine that a replacement (6351GG) will be expensive. There are probably.no second hand units available locally, it is a rate car here. New spares from the dealers are about double the UK price.

I intend to open it up to see if repair is possible, but does anyone know what is the typical failure mode? Are strings of LEDs connected in series?

[Dormouse]

Vibration can cause joint failures. Look for poor connections first. If the individual LEDs can't be removed easily, get ones with long flying leads to re-connect at the back of the unit and hot glue the leds over the existing ones.

You can get them in all sizes and powers to match what you have. Hot glue can be reheated to remove the LEDs in the future.

[GiveMeABreak]

£206.78 UK (Part: 6350GK) New Mike.

There's nothing I cn see regarding the electrical design unfortunately.

There is one on the bay here that ships worldwide:

https://www.ebay.co.uk/itm/Citroen-DS3- ... 3.l4275.c4

and a few others cheaper than that:

https://www.ebay.co.uk/sch/i.html?_from ... K&_sacat=0

[xantia_v6]

Thanks for the info. It is actually the tail light that I need. 6351GG


I can see that the LEDs are surface mounted to a flexible PCB, so maybe it is a PCB failure, which should be repairable.

The first job is to get inside. I will try warming it up to soften the glue.

[GiveMeABreak]

Oops, I assumed incorrectly third brake light as they're the ones with the LEDs usually.

It seems that these are a right royal pain to do by all accounts.

[xantia_v6]

Partially disassembled

I found a local company that repairs LED light units, but decided to have a look inside...

The outer lens is glued on, and the joint needs to be carefully broken and/or sawn apart.

There are some screes inside holding the reflectors and PCBs in place. On unplugging a PCB edge connector I found...

Corrosion 1

Corrosion 2

Unfortunately this corrosion is not the source of the problem, after cleaning it up, there are still about 10 LEDs out. What I did find was that if you press gently on the lens of any of the faulty LEDs, it springs back into life, until you release the pressure. It is not a problem with the board soldering, it is a problem with the connection between the die and leadframe, Given that all the LEDs have been subjected to the same moisture, the all (40) need to be replaced. I wish I could find exact specifications for them.

[xantia_v6]

I think that the LEDs are in PLCC4 package, and operate at 2V. I presume that they are 50mA nominal current, but don't know the spec for lumens or the nominal wavelength (especially for the indicators). It appears that stop/tail use shared LEDs driven with high/low current.

[GiveMeABreak]

What are you going to do - get a second hand lamp unit or pursue it with a vengeance?

[RichardW]

New units are over £500..... Plenty spares on eBay here around £100-£130, if you can't fix it, I can get one and send it over.

[xantia_v6]

Thanks for the offer Richard, I will attempt to replace the LEDs myself. You will hear about it if it goes wrong...

I am buying these LEDs: https://docs.rs-online.com/ae6a/0900766b80d15528.pdf which are physically identical to the originals, but better quality I hope.

[CitroJim]

You will hear about it if it goes wrong...

What we really want to hear about is a great success Mike

[xantia_v6]

I nearly forgot to finish thi topic. I ordered 20 orange LEDs and 60 red LEDs from RS and they took about 10 days to arrive (probably from the UK). This is enough to refurbish 2 tail lights.

I unsoldered all the original LEDs using a cheap hot air rework station (as available on sites that sell cheap Chinese tools). Noting which board had the yellow indicator LEDs.

The new LEDs came with a warning that the plastic cases will not withstand reflow temperature, so I tinned each pad on the PCB with leaded solder and hand soldered each of the 160 pins with the finest soldering iron tip that I could find.

New LEDs on tape strip

After testing, I glued the housing together with a clear silicone sealant intended for sealing roofing gutters, I chose it because it claims to have UV protection.

The job is a success. The minor mistake is that the indicator LEDs should be yellow not orange, personally I prefer the deeper colour, but with the Harvard lights on, they do not quite match the other side.

[Dormouse]

Well done for persevering and researching this. It is a daunting job and so easy to screw up. I take it you won't be starting a mini production line anytime soon.

[GiveMeABreak]

Yes, good job and far more patience that I have!

[CitroJim]

First class Mike! Well done