C3 Pluriel - Flashing rear number plate lights

[Pluriel-Andy]

Hi. New to the forum so please be gentle.

I've had my 2009 C3 Pluriel Cote D'Azur 1.4 petrol for about a year. I recently noticed one of the rear number plate lights was out and so replaced both. The replacements were l.e.d. type. On completing the job I switched on the lights with the ignition off to test and ensure all was OK. Both number plate lights were flashing. Sidelights were normal. I thought I had been sold some odd bulbs for customizing or whatever and bought some regular (incandescent) bulbs and put them in. They too were flashing when tested. That set me thinking so I tried starting the car to see if that changed things. It did, the lights stopped flashing and were on full time. So then I refitted the l.e.d. bulbs as they are brighter and said to last longer. They too are fine when the ignition is on.

So the car is OK and as far as I can tell road legal. The number plate lights may always have flashed and I just hadn't left the lights on when I left the car before. The flashing is still bothering me. To be clear its not a bright the a bit more dull random flicker that you might get from an earth fault, it's a full on then full off regular flashing as though it is designed. It is not affected by putting more lights on (hazards) and is both regular and at a different frequency to the hazards.

This seems to be a designed system but I cannot figure out why its there or what it is supposed to do. If it's a warning who is it warning and of what.

Any ideas as to what is going on would be welcome, particularly from a Pluriel owner who might be able to inform me if their car does the same.

I really like my Pluriel. I call it Aquarium as it is always full of water. If I could only stop the leaks it would be my ideal car. Unfortunately I have come to realise the futility of that task as any part that needs replacement to seal a leak would need to be new and most, if not all, are simply not available any longer.

Thanks.

[GiveMeABreak]

LEDs will flash if not CAN compliant as they do not draw enough load on the circuit, leading to errors.

Either get some proper CAN compliant replacements (but be warned they will be illegal if too bright and cause distraction to drivers following you) - or stick to halogen bulbs as intended. As long as the number plate is illuminated you shouldn't need to worry about the brightness - it's not for your benefit, just the law and original bulbs are compliant.

[Pluriel-Andy]

Thanks for the reply Marc.

I'm not sure about your answer but I've been wrong before (often!!).

The bulbs were advertised as CAN compliant although the supplier (eBay) may have been fibbing,

Would the two lights flash in tandem if the problem is as you say, or would it not be a case of random flashing independently. Also I don't understand why the lights would flash for the reason you give when the ignition is off but illuminate full time when it is on either with the engine running or not.

I tried re-fitting standard incandescent bulbs and they still flash.

I've been trying to find an explanation and am wondering if this is somehow related to the 'economy mode' that flashes on the car display screen and that I do not have a clue about. All I know is that it affects which electrics work with the ignition off, and seems to reset once the engine is started. My impression is that it is some sort of battery saver. Could this have something to do with the flashing? If so it seems a strange way to warn the driver.

Thanks again.

Andy.

[GiveMeABreak]

Nothing to do with economy mode - that only affects equipment in the vehicle to prevent battery discharge like the radio and electrical accessory power outlets etc.

If you are saying that with normal filament bulbs fitted AND NO OTHER LEDS, the number plate lamps are flickering, then you have an electrical problem on the circuit. I suggest you resolve that first before changing bulbs to non-standard ones to eliminate the issue without factoring additional problems attributable to the LEDs.

Yes LEDs can flash or remain on before dimming for a while when the vehicle is locked due to residual current - as said LEDs are low power consumers compared to filament bulbs.