I think you might be right - i will try
one thing to confirm, I have tried every combination, turn off, turn on, press X/Y/Z axis, heated bed etc and all fan is working as expected apart from Extruder, this is the only thing that turns off all fans
if i do not turn on extruder everything works as expected, with fans coming on when steppers enabled/temps going over 50C and then turning off when disabled/temp drops below theshold
im not sure if there is a maximum amount of defintions for calling Heater_Fan: “Extruder”? because I call it 3 times, I have deleted the call but of course Heater_Fan defaults to extruder
I have tried removing " Extruder" from Heater_fan PSU Fan and it finally works expected!
It seems not to like calling temp request from both Heater Fan in 3 places?
Edited - not Controller Fan MCU, it was Heater Fan PSU