I have a Ge refrigerator side by side Model is GSS22JFMBWW and my freezer keeps frosting up I had tech here 3 months ago and he told me about the heater so I went out and bought one and it worked until Saturday I checked the heater and it tested good, what can I do to fix this?

PLEASE HELP

How did you test the heater? Did you test for power to the heater when the unit goes into its defrost cycle?

In a self defrosting refrigerator the 3 parts that go bad are:

1. Defrost heater faulty.
2. Defrost limit switch faulty.
3. Defrost timer faulty.

Well, you changed out the heater so it's #2 or #3 that went bad.