Tennessee Code Title 56. Insurance § 56-7-1101

(b) Any provision of subdivision (a)(1) or (a)(2) to the contrary notwithstanding, where the only insurance coverage provided by the owner of the vehicle is under a garage policy, then any coverage that may be available to the permittee shall be primary and the coverage under the owner's garage policy shall not be applicable unless and until the limits of all coverage available to the permittee shall be first exhausted; provided, that when any non-owned vehicle is in the possession, custody or control of a person who is in the business of storing, parking, servicing or repairing vehicles, then any insurance available to the owner shall not be applicable unless and until all insurance that is available under a garage policy of the person in possession has been exhausted.

(c) When a claim arises out of the operation of a motor vehicle that is leased under a written lease agreement, and pursuant to which agreement the lessee provides coverage for the vehicle, then any other coverage that may be available for the vehicle through the lessor is not applicable unless and until the limits of all coverage provided by the lessee for the vehicle first are exhausted.

(d) Subsections (a) and (c) are effective as to all policies written after May 7, 1973, and to all renewals of existing policies made after May 7, 1973. Subsection (b) is effective as to all policies written after April 5, 1974, and to all renewals of existing policies made after April 5, 1974.