Musannaf Ibn Abi Shayba 1:80

Yazid ibn Harun narrated to us, he said: Al-Jurayri informed us, from Urwah ibn Qabisah, from a man from 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 rinsed his mouth three times, and inhaled water into his nose three times, and washed his face three times, and his forearms three times, and wiped his head, and washed his feet. Then he said: "And know that the ears are part of the head." Then he said: "I have sought out or intended for you the ablution of the Messenger of Allah, may Allah bless him and grant him peace."