Please give any daleel that this is a part of wudu.Even a weak hadith.As this is mentioned in a response of one of your questions about how to make wudu Jazakallahu khairun.
Answer:
It is Mustahabb to wipe the back of the neck during Wudhu.
and Allah Ta’ala Knows Best
Mufti Ebrahim Desai
FATWA DEPT.