For the last couple of months my amber lights in the door mirrors have been permanently on, until the car is shut down. Took it for its MOT today, its second since it’s coming up to its fourth birthday and still has two years of extended warranty left. I had asked the main dealer to sort it at MOT time when I booked the MOT.
They plugged their diagnostics in and couldn’t find a fault but obviously there is one and I’m not sure how many safety systems are compromised by this but probably more than one rear crash mitigation ones. Pretty sure there’s a faulty connection to a module or sensor either in the rear right hand side door or the sidewall further back towards the rear.
It came about while driving at less than 20mph on a very wet day in the local town.

Any ideas?

It’s going back for further investigation and rectification in about a fortnight, but the dealer is so far clueless so if anyone has experience this problem, it will help them out greatly if there is a solution out there.

Which amber light? Mine shows a small dot at slow speeds all the time (I think it says the system is working but not active at that speed , but that changes to being off when driving normal speeds and the car icon appearing when it needs to. V8 or else ...

The very same amber lights. There is no ambiguity possible as there are only two, one in each door mirror. As explained, mine now stay lit permanently [which includes at all speeds, to make it quite plain for you] apart from when the ignition is switched off. The car icon remains dark and I never saw that even when the system did work. Neither do I see such a symbol on my Defender’s mirror on which the blind spot warning works perfectly.

I know perfectly well how it should work. My issue is that it doesn’t work any longer on my RR and would appreciate the view of anyone who has an idea of why and how to repair it.

I think it works off a radar sensor in the rear bumper, so check there for any obvious damage or loose connection.

Also, I think the system is disabled when the tow bar electrics are plugged in, so maybe check there too.