§ 313. Guaranties to sellers of liabilities of buyers under retail
instalment contracts. No guaranty given to the seller or to the seller
and the seller's assignee of the liabilities of a buyer under a retail
instalment contract shall be valid unless the guaranty is incorporated
in or endorsed on the contract or identifies the contract and specifies
the time balance thereof or, if the guaranty relates to one or more
future retail instalment contracts, it limits the liability of the
guarantor to contracts dated within a period of two years from the date
of the guaranty and sets forth the maximum amount for which the
guarantor shall be liable. A copy of the guaranty shall be given or
mailed to the guarantor upon or immediately after the execution and
delivery of the original guaranty by the guarantor.

As used in this section, "retail instalment contract" and "contract"
include a retail instalment contract as defined in the retail instalment
sales act, constituting article ten of this chapter. This section does
not apply to a guaranty made by a seller or a holder of a retail
instalment contract.