Whirlpoll Freezer model EV190NXWN00 not freezing

it sound like is not defrosting if is upright freezer. open the back wall jerry if that evaporator is full of ice then it has cut off all the air flow and in return that is why is not freezingif you know how to use the voltage meter you might need to check continuity on the heater if it check ok then repl the bimetal part# 4387499 and timer 482493 when repl time follow the wiring schamatics realy carful look for the right clor harness in the instructions and then just let it defrost or use the hair dryer