Ariz. Rev. Stat. § 28-4532
A. A vehicle that is owned by a dealer and that is otherwise required to be registered is exempt from registration while the vehicle is owned by the dealer. A vehicle owned by a dealer may be operated under owner responsibility on public highways and streets according to the following provisions:
B. Dealers' plates shall not be used on the following dealer owned vehicles:
C. Except as provided in subsection B of this section, a dealer plate may be used on a dealer owned vehicle as follows:
3. When operated by a person who is lawfully engaged in a contract with a dealer to perform any of the following at a permanent site or location where the person conducts business: