If you select anti ice ON while the thrust is idle without keeping 45%N1 you will get a LOW IDLE light above the engine primary display(somehwere in the middle
)
That light doesn't exist in the NGs - which is the only variant I'm in right now.
Does anyone know where to find a reference for the min N1 for icing? I think it was edited out when they updated the engine controls, but I'm sure someone knows where to find it.