Freezer did NOT have extra frost build-up. Was unsure if defrost thermostat was needed, but for worth ordering it to have on hand just in case. Defrosted and cleaned fridge, removed freezer panels and saw the fan was not spinning, tapped the fan blades and it started spinning up again, so I figured it must be a problem with the fan motor.
Easy install: removed freezer panels, removed metal bracket that held motor, unplugged power and unplugged ground cable. Removed fan blade and 2 silicone rings from the old motor. Put the new motor in the bracket, placed silicone rings back onto the new motor, popped old fan blade on mew motor. Screwed bracket back into the fridge, plugged in power and ground cables. easy fix. Tip - Take a photo of the old motor in the freezer so you know the arrangement of motor and cables in the bracket for reference just in case you get confused.