Musnad Ahmad 3:31

Yazid ibn Harun narrated to us, al-Jurayri informed us, from Urwah ibn Qabisah, from a man of the Ansar, from his father: That Uthman said: "Shall I not show you how the ablution (wudu) of the Messenger of Allah, may Allah bless him and grant him peace, was?" They said: "Yes." So he called for water, and he rinsed his mouth three times, and he blew water from his nose three times, and he washed his face three times, And his forearms three times each, and he wiped his head, and he washed his feet. Then he said: "And know that the ears are part of the head." Then he said: "I have performed for you the ablution of the Messenger of Allah, may Allah bless him and grant him peace, with precision."