What is the ruling on wiping the head during ablution if the wiping does not cover both sides of the head and the thumb is not used to wipe behind the ear?

Scholars have differed regarding wiping the head: whether it is obligatory to wipe the entire head (the view of the Maliki and Hanbali schools), or if wiping part of it suffices (the view of the Shafi'i and Hanafi schools, and a narration from Ahmad).

According to the view that wiping part of it suffices, the ablution is valid, and there is no need to repeat past prayers. However, it is preferable to wipe the entire head in the future.

As for the method of wiping the head by placing the thumbs on the temples and extending the fingers, this is an interpretive method to ensure wiping the entire head, and it is not obligatory. What is important is that the wiping is performed in the required manner.