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Riding to work on my 2004 F650GS last week the indicators stopped working completely. When I rode home they worked again then stopped. The same for three days before they gave up completely.
Fuse was good (horn/light/brake lights still working) and switched the relays around to no avail.
Eventually tracked it to a broken diode. To get to it remove the panels, air box, battery and battery tray and the two screws holding the electrical tray in place. Underneath are three small plastic clip box things. Inside each is a small diode (about the size of a hamster dropping) soldered to an electrical connector. One of these was broken in half. BMW charge about £25 for a new one BUT search eBay for a BYV27-200 and you will find one for about a quid. I was lucky and found a seller down the road from me, JH Components near Lichfield, who I was able to pop over to and collect. A quick bit of soldering and hey presto fixed. Then it was just a case of reassembling everything. Whilst you have it apart check the other diodes as well.
Hope this helps someone at some point!!
 

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As far as I can see, two of the diodes electrically isolate the hazard warning circuit from the indicator circuit and, if one of these fails, it will simply take out the hazard warning feature. However, the power to both circuits comes via the third diode which, presumably, is the one that failed in your case.

I will have to have a look at some other equivalent wiring system but it does seem BMW used a lot of diode in the dual spark F650GS which may have been to save on wiring:think:
 

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Good skills - thanks for sharing the knowledge :thumb:

SteveT

:cool:
 

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Riding to work on my 2004 F650GS last week the indicators stopped working completely. When I rode home they worked again then stopped. The same for three days before they gave up completely.
Fuse was good (horn/light/brake lights still working) and switched the relays around to no avail.
Eventually tracked it to a broken diode. To get to it remove the panels, air box, battery and battery tray and the two screws holding the electrical tray in place. Underneath are three small plastic clip box things. Inside each is a small diode (about the size of a hamster dropping) soldered to an electrical connector. One of these was broken in half. BMW charge about £25 for a new one BUT search eBay for a BYV27-200 and you will find one for about a quid. I was lucky and found a seller down the road from me, JH Components near Lichfield, who I was able to pop over to and collect. A quick bit of soldering and hey presto fixed. Then it was just a case of reassembling everything. Whilst you have it apart check the other diodes as well.
Hope this helps someone at some point!!
Hi is there an easy way to get to the diodes as We can’t seam to reach them?
 

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Hi is there an easy way to get to the diodes as We can’t seem to reach them?
The simple answer is no, you have to strip the panels, battery, battery tray, electrical holders etc as described above, a knowledge of electrics and of how to test them is also helpful if it doesn't have a clear break, one point to make is, if it is a broken diode it would help having one before stripping the bike...
I'm sure if you let people know where you are there will be someone local to help :)
My bike shop is in Harlow Essex, if you are local to me I'd be happy to take a look 😊
 

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Hi. I was delighted to find this post since it described exactly the symptoms I am dealing
with. Yesterday I accessed the diodes and sure enough two of the three were broken. I soldered in two new ones and put it all back together. Now the near side indicators work properly. The offside operate but at a slower speed than normal. Most worryingly however, is that now the starter fails to engage, it was fine before I accessed the diodes!
HELP! Any instructions gratefully received.
 
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