GE Profile PFS22SISCSS defrost thermostat parts?

This is defrost thermostat part number 625 in fridge section.

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This is part number 621 in the freezer section:---

Defrost Thermostat:--

And this is part number 620 in the diagram:---

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Basically all this 3 parts looks near to same, may a wire long or short.And function on this 3 parts is near to same.--------

Click this link to order parts:---

http://www.searspartsdirect.com/partsdirect/part-model/GE-Parts/Refrigerator-Parts/Model-PFS22SISCSS/0432/0161000/G0712221/00002?blt=06&prst=0&shdMod=PFS22SISCSS