2080 Super fan issue

Good day everyone. Recently my gfx card has started to go full speed on the rear most fan. (Towards the display connectors)

The other fans are standing still (they totate freely when nudged with a finger). This happens when gaming or just watching YT. And no matter how long i leave the PC in idle, the single fan keeps reving at full tilt, the others stay still.

The fan is told to go 100%, the rpm feedback sais the fan is not rotating. (Graph in MSI afterburner) Manually adjusting the fan speed in MSI afterburner doesnt change the running fan or the stopped ones.

I did update the driver to the newest studio one (dont need the gforceexpirence stuff) did a reflash of the bios i got from a site (tomsHW i think, did make sure its the right one aswell).

I am open to take apart the card, warranty is over anyway. What should i check for, first in software, afterwards in Hardware? Specific supplies i need before hand? (Got an ifixit kit for screwdrivers)

Thank you very much for pointers.