This thread describes how BMWs inept (charitably put) design of the fuel pump controller connection on most R12 bikes can leave you with a dead bike, especially if you ride in the rain. I am by no means the first person to comment on this (as a web search will show you) but most have talked only about how to fix it. Much of this thread is about how the BMW design is a failure waiting to happen, with recommendations on pre-emptive maintenance.
What happened to me? My 08 RT simply crapped out today in nice weather while going on an errand. It died and could be restarted, multiple times. Sometimes it quit again almost immediately or in a couple hundred yards and sometimes I could ride it 5 miles with no problems. My GS-911 showed a 10168 code, electric fuel pump failure, so I pulled the left side cover to examine the fuel pump controller and connections, a well known problem.
Let's start with a broad view photo to set the scenario. The silver circle in the photo is the well that contains the fuel pump controller. In the photo, the controller has been removed. Notice that the fuel pump controller/well is on a slope,at the front of the fuel tank and that the removed controller occupies the low spot in that well. Therefore, fuel pump controller connections are at a low point in the well where any water that penetrates will collect. A smart engineer would make a well with an electrical connection self draining so that any water which penetrated would also flow back out and not build up to short the connection. Really smart engineers wouldn't put the connection in a well, let alone a well at the front of the tank where heavy rain can reach it while riding. BMW's engineers aren't smart enough to have done either.