2021 R18 but topic would generally apply to all CAN bus BMWs.
I had to replace the plastic cruise control controls on the left-hand switchgear. Like most of my work, I fixed one thing and broke another. Now the cruise control works, however, the horn and turn signals stopped working. The other functions on the switchgear work - cruise control, flashers, high beam, menu, aux lights.
All the functions run off 3 CAN bus wires - 12V, CAN L, and CAN H. They are getting 12V, 7V, 7V to ground with ignition on. So, I am thinking the problem is on the switchgear.
I have disconnected the battery to reset the bike control units but no help.
Is there a way to read the CAN bus data to see if the horn and turn signal buttons are sending any data?
Any other diagnostic advice is appreciated.
Pic attached. Four circled buttons are left, cancel, right. Bottom is horn.
https://imgur.com/a/XSyNCBs