Samsung RS21FCSV American type

So this makes a terrible noise when the fan starts it seams to be a common fault I have looked at other posts and videos of what to do but I can’t seem to visualise how, when it seams to be ice cause I g to the pan to make this noise that when you remove the build up of ice and clean out the drain pipe that you don’t actully clean anything off the fan infact you don’t even get to see th fan. Can any tell me how clearing away the ice from the cooling and heating coils releases the fan from making the noise