I changed the extruder fans of my Anycubic i3 Mega but for this to work you have resolder the connectors on the PCB. Alternatively you could move the PCB to another position.
I made a holder for the PCB to place it on top of the extruder case. Just use the existing screws and slide the cover on top. You might as well need to sand some off the cover to be able to slide it in...
Please comment if you have any questions or suggestions