S.D. Codified Laws § 37-5-12.4
Any manufacturer or supplier of merchandise as defined in subdivision 37-5-12.2(5), (8), or (9) that authorizes a dealer of such merchandise to perform the warranty work is obligated to provide that dealer reasonable compensation for diagnostic work, as well as repair service, parts, and labor to the dealer. Time allowances for diagnostic and performance of warranty work and service shall be adequate for the work to be performed. The hourly labor rate paid to the dealer for warranty services may not be less than the rate charged by the dealer for like service to nonwarranty customers for nonwarranty service. Reimbursement for parts used in the performance of warranty repair may not be less than the current retail rate customarily charged by the dealer for the part or parts.
SDCL 37-5-12.4