Citroën DS3 brake lights flashing while driving

[MrS]

Hello!
I'm looking for advise on a issue I'm having with my 2012 DS3 1.6hdi
The issue I'm facing is that my brake lights are flashing/flickering when i am giving gas(all brake lights). When coasting the lights are off and when braking they work normaly. So its a rave party for the people driving behind me
Cruise control is not working either, limit is working.
I have replaced my brake light switch and inspected connectors for ABS module.
Start stop system is also defective with no communication with generator ECU.
Any help would be highly appreciated!

[GiveMeABreak]

Have you replaced ANY bulbs with LEDs?

LED bulbs can result in insufficient current being drawn and this can cause rapid or intermittent flashing. on the circuit. If not check the bulbs and bulb holder fittings to ensure proper contact.

Also check the earth wire pin to the rear lighting plugs - make sure these don't show signs of burning of the plastic near the pin holes.

Get a diagnostic done as usually the cruise control will be deactivated in the event of an engine management fault or an electrical / communication fault with the ESP / Engine ECUs / circuits. You may well have a few fault codes that need to be investigated.

[MrS]

Thank you for responding
Only turn signal bulbs are 3rd party LED. Rest is facelift lights with only LED bulbs for brake lights
The interesting thing is that the brake lights are not flashing when going in reverse.
Can it be that the BSI needs to be sent for reman? I did try BSI reset but but not sure if i did it correctly so i will try again a few times.

[GiveMeABreak]

That'll be your problem. The circuits are not drawing enough power (load) so this causes the rapid / intermittent flashing. Regarding reverse - that's most likely because you don't have LED lights for reverse and the circuit is drawing sufficient power. The whole of the rear light clusters generally use the same earth for all the lights.

It's never a good idea to put LEDs into brake lights or tail lights as they are generally too bright and can blind drivers at the rear at night and can get you into trouble. They are not legal for road use over here incidentally. If you put your normal filament bulbs back in that should remove the circuit. If you have diagbox, I can almost guarantee you will have logged faults in the lighting circuits when using LEDs.

[Hagrid]

IIRC in the UK, light units fitted to cars must be approved for use, but note that I didn't say light bulbs. In fact, LED lights are not technically illegal in themselves, but neither are they legal - UK law has not caught up with the technology.

All light units designed by mfrs for their cars are approved for use with a specified type and wattage of bulb, but when this system of approval was set up all bulbs were halogen, or at least filament, so it remained only to specify the bulbs by their fitting, for example H4, or wattage.

So approved light units only meet their legal approval when fitted with, for example, H4 bulbs. It is still usual to assume that this is all that 'H4' means - but unfortunately the H stands for halogen and so these car light units are only legal when fitted with halogen H4 bulbs.

Therefore, fitting existing light units with LED bulbs is illegal in the UK because the units were not approved for use with LEDs, not because LEDs are illegal; or were not approved for use with bulbs of lower wattage than the approved figure.

That explains why some modern cars have perfectly legal LED lights - those light units have been approved for use with the LED bulbs which are in them. It would even be illegal to replace their bulbs with halogens if you could - probably not as mfrs are taking advantage of LED lifespans to make owners replace whole light units instead of just their bulbs.

[MrS]

Thanks guys
On my 2012 i have the facelift taillamps and headlights installed which has LED brake lights as standard, this is also why i can see it flashing on retro-reflective signs i drive past.
I have now installed standard indicator bulbs and the issue is still present when driving :/
I am really in between options of sending my BSi for reman or buying a new alternator since start stop ecu is reporting no communications with it and maybe its related..
BTW, any good places to get wire diagrams from? i would like to measure for short to ground on can signal from dynamo.
I really do appricate the help this forum is giving me and has given me before, Thank you!

[GiveMeABreak]

Pop your VIN up for me so I can see exactly what you have fitted. That wills ave me some time. SOme cars had LED lookalike lighting - but were not actual LEDs.

@Hagrid I'm aware of the LED issue - and only left it at not road legal here to mean just that - not for public road use here, but did not want to go into the big Type Approval issue as he is in Norway, not the UK or the EU (only in the EEA), so may not even be relevant to the OP. But LEDs in Filament designed housings are risky and potentially dangerous with their light output which is the point I was trying to make.

[Hagrid]

I quite understand Marc. I thought the info might be useful for UK readers of this thread too.

[GiveMeABreak]

I dabbled with them years ago in one of my cars when the LEDs were the size of Christmas Globes - they weighed a tonne and were useless which 'LED' me to the conclusion to leave well alone on the rears

[Hagrid]

Ah, so the light emitted, then!

I bought some neon LED rear clusters with progressive indicators to add to the back of my 2003 berlingo, then after buying them I decided to research legality. Oops! Should have bought them from Ring, not from Chinesebay!

I could install them if I also keep the original rear lights for legal compliance, but their sparkle has diminished somewhat. They'd also probably need a bypass relay.

My first idea was to replace the original lights with traditional beehives, but that idea went south. You can't add style to a Berlingo!

[myglaren]

I have just fitted LEDs in the reversing lights. They are much brighter but no better as the reversing lights are above the number plate and illuminate straight behind, no use for reversing in between parked cars. Only a couple of quid and came with a pair of 50W ally resistors which I didn't bother using so the Civic probably isn't CAN bus. Hasn't complained anyway.

[Hagrid]

I have no idea what shape/form the Civic rear light housings have, but could you put small pieces of dished tin foil above the LEDS to act as reflectors? Obviously, keep the foil well away from any electrical contacts!

You might even be able to shave the end profiles of the LEDS to change their lens properties.

[myglaren]

There may be scope for some modification. Different LED units may be better, I bought cheap ones to be sure of the fitting - the handbook describes replacement but no indication of bulb types. Most are around £15 a pair so wasn't risking buying something that didn't work.

It is partly vision out of the Civic though, complete rubbish compared to the recently retired C5.

[MrS]

Pop your VIN up for me so I can see exactly what you have fitted. That wills ave me some time. SOme cars had LED lookalike lighting - but were not actual LEDs.

VF7**************[VIN obfuscated, can be read by forum staff]
You would likley find the parts for the pre-facelift lamps when searching by vin. I have always believed that the facelift lamps are all LED except indicator, reverse and fog bulb. But i might be wrong..
Added a picture of the pair i have installed on mine.
I will connect a scan tool to have a look if there are any new codes since last time when i get a chance. I had an issue with ESP flashing every time i was accelerating but that turned out to be a blown fuse for the ABS unit, this is also why it would be interesting to have a wire diagram to see if ABS unit is controlling the brake lights or sending a messed up speed signal or something which i think could point towards an internal fault with ABS/ESP ecu.

[GiveMeABreak]

We use PSA directly for the info - not some dodgy site so as long as we are talking about standard factory fit options as your car rolled off the production line it will be accurate.

So as I suspected your vehicle does not have LEDs - they are standard bulbs.

Lamps 10, 12 & 13 were never LEDs - only bulbs.
Lamp 11 could be either depending on market and build date.

Your VIN indicates that lighting option [1] was fitted to your car, which consists of: 10, 11 (bulb not LED), 12 & 13 which are all filament bulbs.