Problem with replacing the electrics is that BMW are no longer using the original suppliers and some - most- of the stuff they are selling is junk.
If you look on Ebay for switches you will see that vendors with NOS, marked Hella , are asking, and getting, twice the list price of the current junk, and secondhand stuff off low mileage bikes is going quickly for more than the current list price.
Most of the wiring failures are within the final couple of inches of the terminal, and I carry a selection of terminals pre crimped to six inches of wire and a Lock It connector on the other end, on my 400,000 km plus G/S. And a couple of long leads with crocodile clips either end so I can bypass the switch and hot wire arything
So far I have used three of the terminals, but always one someone else's bike!