The majority of LED number plate lights are not worth a jot they are normally of Chinese origin and have under perfect conditions a limited lifespan, in a car with varying voltage and no means on a older car of controlling spikes they are not very good I notice that here in Germany that LEDs that are for sale vary those that are very expensive and have a traceable history seem to work ok.

As a mater of interest LED lights bought by major of reputable companies are normally in the middle of a production run where the colour and quality is better the production on the outside of the main batch are sold off to make cheap lights and then of course the Chinese copy them and make them in less than clinical conditions.

I suggest its your own choice is to buy bulbs that are from a reputable source and that they are fitted correctlly as watertight and with as little condensation as posible it may also may worth just checking the voltage at fitting a fault in the Canbus can cause upteen problems.

I have read on other forums that they can cause problems if used on a car with Canbus or if the wattage is below one watt as the system then thinks they have failed.

I'm trying to find a good source too as there seems to be a large number of cars going around the roads with one or both registration plate lights not working. I'd rather fit something that works and will work for a long period of time.