Might be a stupid question, but I'm asking anyway My RR of 5 years has had 2 new FSR in that time and think she needs another But have been reading about a rear FSR too, do these fail very often? Seen a million and 1 guides/videos on the front on under drivers dash, but what about the rear one, do they fail?

And if so, how would you tell which one had given up?

No reason why the rear one shouldn't fail, although it probably gets used a lot less than the front one.
I think the only way you could test it is to use it and see if the rear fan speed varies smoothly as you change the speed by rotating the wheel up and down.
The two fsr's are totally independent of each other.

As above but also the two are the exact same part numbers so, if one fails The other must too

^^^

Are you sure? Replaced my front FSR three times and rear fans still behaving as expected (although I don't get much heat!) .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

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