Does wiping over ones khimaar and turban replace wiping over the ears, due to their both being part of the head? 
My opinion, and Allaah knows best, is that at times it does replace it and at other times it doesn’t. As for the condition in which it does replace wiping (the ears) then it is the state when the turban or the khimaar covers the entire head, including the ears. Thus, in this condition, the hadeeth would apply in that they (ears) are both part of the head literally.
As for the other condition in which it is not sufficient to just wipe over the turban or the khimaar, then it is when the turban or the khimaar does not cover the ears. This means that the turban is wide or aloof from the ears. Under these circumstances I hold that the authentic hadeeth about wiping the head itself. This is such that three ways of wiping the head have been established on the Prophet, sallAllaahu ‘alayhi wa sallam:
The first way: This is the most common and normal of his ways and it was that he would wipe all of his head directly.
The second way: If the turban or the khimaar covered the head, then it was sufficient to just wipe over the turban or the khimaar, exactly like the head.
The third and final way: And this is the area that requires evidence and needs speculation. And it is when the turban would cover the last part of the head, yet expose the front of it (forehead). In this condition, the Prophet sallAllaahu ‘alayhi wa sallam would wipe over his head directly and then grasp his turban.
 Translator’s Note: The Prophet said: “The ears are part of the head.” [Reported by At-Tirmidhee (37), Abu Dawood (134) and Ibn Maajah (444) and declared saheeh by Shaikh Al-Albaanee in As-Saheehah (1/36)] So we are obligated to wash them when taking wudoo and ghusl even though the ayah concerning wudoo doesn’t mention the ears but only the head. This question is based on this principle in that if we are permitted to wipe over certain garments in replacement of the head, are the ears included in the same manner?
[Al-Asaalah, Issue #8]
Source : Fataawaa of Shaikh Al-Albaanee (rahimahullaah) – From Al-Asaalah Magazine Issues 1-21
Translated and Arranged by: Isma’eel Alarcon