Toon Shading Issue
 

I'm just getting into toon shading for models. Up until now I've been using regular colors which have been working just fine, but as soon as I attempt to use my own drawn textures the shader shows up as black in Maya. Once it renders it shows up fine, but it's difficult to light a scene when a character looks completely black. Would anyone happen to know why this is happening?

Thanks!

https://drive.google.com/open?id=1As...HBZ0oanMLaIxzM

https://drive.google.com/open?id=1K2...tCQIwcvZEW8Dvb