I think this has more to do with the command from the ECU and not any loose connections. The tests between the ECUs were only a couple minutes apart, and the only things touched were disconnecting the battery and R&R the ECUs. Function was always verified with the stock ECU after testing with the flashed one.jimmy57 wrote: 02 Jan 2019, 13:27 Yes, I don't recall there being any noticeable differences in any of the Motronic versions using two speed fans.
If you are seeing differences then check the two pole grey connector (could be black) on the fan relay. Those round female connectors have the rubbery surround material crumble and the connection can come loose. Then you can have low work and then no fan when it needs high or a delayed fan where hi is triggered for a short run and it loses fan operation when it reverts back to low but has no connection to make low speed run.
Looks like there is still something in the code that needs to be addressed.
Thanks!