Hello.
I have done some research on fuse 31. You have a short on the wiring for fuse 31. It could be somewhere in the wiring or it could be a component on the wiring leg that feeds fuse 31. If it is a shorted wire somewhere it could take some time to find and might need hands on searching from a dealership.
However some things you can check are:
Fuse 31 is for the instrument cluster, the chime module(under front driver kick panel), thermal oil level switch(oil level sensor mounted under the veh at the oil pan), and clock. In order to find the problem you will need to isolate the wiring and comonenents. I would start by disconnecting the control modules one by one and putting in a fuse and see if it blows again. I would suspect the oil level sensor for popping the fuse as I have seen it before. You will have to disconnect the wiring to it and recheck the fuse operation.
I hope this information will be helpfull to you. This type of problem can be difficult to find even by the professionals.
BMW Mechanic
Level 1 BMW Master Certification, 9 Years Dealer experience, Team Leader, Shop Foreman