Moin Jürgen,
(I continue in English if it would be ok...)
The Harness controller looks like the Thunder Heart module, what is connected to the new Harness. I only have a schematic of a 2005 Ironhorse, what had this controller implemented and attach the schematic and the schematic of the 2008 BD, what is similar to your bike.
You might check pin 35 of the module, if the ignition voltage is present, when the spark fail. However, I don´t know if it is still the exact module, what BD use but maybe it helps.
Btw, I had with my own first EHC before also a similar issue when a high current after market ignition was implemented in the bike. It resulted that the EHC switched off the voltage to the ignition sometimes after some minutes and sometimes after a hour, when the internal polyfuse was warm and tripped. This issue was only sometimes present and cost me a bit time to identify and solve. However, Thunder Heart deal since some years with Harley and S&S engines and ignitions and I´m pretty sure, that these guys know how to handle also high current after market ignitions.
Viele Grüße aus dem kalten Deutschland!
Axel
