Id say it the lamp failed or at least the LEDs to produce the yellow colour could be the PCB inside which is likely hard to get at or the strip itself can no longer produce yellow. Prices have come down so might be easier to just get another set and fit them might not need the resistors either now as most are plug n play sweeping. These are not genuine LR lights though but to be fair shouldnt make much difference and alot cheaper, there are smoked and clear versions available now so can work quite well with certain colour schemes. If a jobs worth doing, get a someone who knows what they are doing to do it!

RRS Autobiography Indus
RR P38 HSE V8
RRS Supercharged Santorini
AMG CLK Rear Tyre Shredder

Thanks for the reply.

I was gonna swap the passenger light over and test it.

I was thinking obviously the night running light is the same as the dynamic indicator just goes a different colour so could be the dynamic yellow LED that gones - I'll take it apart and check to see if I can see anything obvious if not I'll get a new light unit, annoyingly...

Yes exactly, if the led has an issue and cant make the colour yellow at any time its new lights Im afraid, but prices are much cheaper now and probably all have the sweeping and cut off function built in these days. Its not a good idea to have only one light connected during testing as the car cant cope with the lighting of only one and can cause an error. Id just get some new lights on order so they will be here with you by the weekend ready to fit. If a jobs worth doing, get a someone who knows what they are doing to do it!

RRS Autobiography Indus
RR P38 HSE V8
RRS Supercharged Santorini
AMG CLK Rear Tyre Shredder

I purchased the new 2018 'aftermarket' lights for my 2015 RRS and have had nothing but trouble. My issue has only been with the brake lights, the worked fine at first then would die out during morning start up and not come back on unless i restart the car, all very confusing.
A local specilist tried numerous things including changing both batterys. in the end i put the original lights back in, the mechanic reset the lights and no issues since.
It could have been an issue with these particular lights but it has been a real headache and a constant worry that i dont have brake lights ! beware! 2015 RRS SDV6 HSE Grey