'fraid not. Although I didn't say so it was the first thing I did. Thanks anyway. Glyn.
I mis-read what you wrote in any event. i mistakenly assumed that you had replaced the flasher unit (any cheap 3pin flasher will work).
The fault of 'nothing but a loud buzz" is a well known one. In decreasing order of likelihood the cause is nearly always one of the following:-
High resistance in the rear sub-frame connector block or the handlebar connector block.
Loss of earth in one blinker light and high resistance in the other (one high resistance or loss of earth on its own won't do it as if the the remaining light on that side is in OK condition it will usually be enough to allow the flasher to operate
Failure of flasher unit itself
High resistance in the handlebar switch (these two group about equally)
wiring damage (remote unless the bike has been in an accident or the harness butchered -BMW make a pretty good harness).
If you replace the flasher and the fault remains then I would still suspect the handlebar switch. you can test the lights/wiring/flasher unit by breaking the handlebar cable connector and using paperclips to emulate the effect of the handlebar switch.
I'd suggest taking the switch apart as an absolute last resort as it is a PITA to both get apart and put back together. I would buy a cheap can of brake cleaner (or contact cleaner if your budget allows) and spray the sucker out thoroughly, followed by WD-40 or CRC.
