Mercy Thompson Series: Books 1-3 by Patricia Riggs (Mass Market Paperbacks)

Moon Called

Blood Bound

Iron Kissed

Mercedes is a Volkswagen mechanic living in the Tri-Cities area of Washington. Her Native American heritage has gifted her with the ability to take the form of a coyote at will. She's surrounded by far more powerful supernatural beings, including werewolves, vampires and an assortment of fae.