unplug ice maker
make sure water valve is indeed in the on position, i changed mine last summer and i surely remembered turning the water back on, which i did not
while power is off to the ice maker, reset the plug in the fridge, did your new whirlpool one match up on the connectors or did you have to add in a matching plug end inside the freezer box? i ask because some come with the correct plug and others don't so you have to guess what goes where as the new icemakers are lacking on schematics
then if all is good
plug ice maker back in and wait 24 hrs
it has to reach an internal temp of something like (don't quote me" 25-35 F before it decides to fill with water.
download the repair manual at Service Documents
they have the secret dometic BIG book on pdf.