i think most of the self level gear is visible when you take out the spare tire holder in the back.

If the over pressure valve is stuck open you should hear the air hissing out.

I would say better odds one of the inflation lines is disconnected. You can use soapy water to help find a leak and also, new ≠ fixed, you may have a faulty air spring, though usually you'll get a sag on one side.

What are the values of each level sensor?

Did you possibly misidentify the fuses? Even if a relay is stuck shut you should have no power at the pump when the fuse is pulled.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)