Q7 Air supension

[southendpier]

I think my air suspension is stuck on the highest setting. The dash fault light is off unless you try and change the ride hight then it goes on. The MMI console states the cars is on the middle 3 of 5 setting and all options other than automatic and comfort are greyed out.

I have been told there is a small levelling control arm that may be dirty or broken somewhere around the rear frame of the car that may be causing the suspension to stick on a fail safe high setting- anyone know where it is so I can check before going off to the dealers?

Ta