Freezer is fine, refrigerator is too warm.

I have a whirlpool refridgerator model ED2FHAXSB03 and I am having problems with the defrost system, it keeps frosting up causing the fridge to be too warm. The defrost heater has resistance and I have already changed the defrost thermostat, but I am still having problems. Is there a way to know if my control board is bad, or is there something else I should be looking at?

Here are your parts
Replacement parts for WHIRLPOOL ED2FHAXSB03 | AppliancePartsPros.com

Here is a tech sheet
https://www.servicematters.com/docs/wiring/Service%20and%20Wiring%20Sheet%20-%20W10142176.pdf

It shows how to force a defrost.
If a forced defrost works then the defrost control board is shot.

I tried both ways on the tech sheet to force a defrost and could not get either way to work. The tech sheet says I should be hearing a relay click, but I did not. Where do I go from here?

You could check the wiring for continuity with a meter.

Since you cannot hear the relay click I would say that the defrost control board is shot. Also by the process of elimination this is all that is left.