Michigan Compiled Laws, Chapter 257. Motor Vehicles § 257.1307e

(a) Unless legally waived by the customer, fail to give the customer a written estimate before beginning work on a motor vehicle.

(b) Charge for work done or parts supplied in excess of the estimated price without the knowing consent, orally or in writing, of the customer.

(c) Fail to give a customer an estimate for the cost, if any, of reassembly, disassembly, or diagnosis.

(d) Fail to inform a customer, at a time before the customer executes a document or engages the facility for the work, by the use of a notice required under section 33,  1 of his or her right to receive or inspect replaced parts for which he or she will be charged in the repair of his or her motor vehicle.

(e) Fail to retain a customer waiver with the records retained by the facility concerning the transaction.

(f) Charge a customer storage charges if there is a dispute concerning repair charges. If a delay in repairs is caused by a lack of parts, a facility may charge for storage after informing the customer of the approximate length of the anticipated delay and of the daily storage charge rate and obtaining the customer's consent to the delay and the storage charges.

(g) Fail to comply with the truth in lending act, 15 USC 1601 to 1667f, and the retail installment sales act, 1966 PA 224, MCL 445.851 to 445.873, if the customer finances repairs through the facility.

(h) Fail in practice to comply with advertised or stated payment policies.

(i) Conspire with another to fix prices.

(j) Conspire with another to allocate the market between them.

(k) Fail to notify a customer of an exchange agreement and charges for exchange parts if the customer wishes to have those parts returned.

(l) Fail to disclose, on the customer's request, the method used by a facility to compute labor charges.