Section 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.