The Texas Comptroller of Public Accounts explains the sales tax treatment of repair services performed on motor vehicle component parts. When a repair person repairs or rebuilds component parts that a customer places in inventory or installs on a vehicle other than the vehicle from which the part was removed, the repair person is not considered to be repairing a motor vehicle, but rather is considered to be repairing tangible personal property. Therefore, the repair person must collect tax on the total charge for the repaired part, including labor and materials. On the other hand, when a repair person repairs or rebuilds component parts that will be placed on the vehicle from which they were removed, the service is considered to be motor vehicle repair, and it is not taxable. Since the repair person might not be able to determine whether the repaired part will be replaced on the vehicle from which it was removed, the customer should issue an exemption certificate that clearly states that the repaired part is being placed on the original vehicle. (Letter No. 200610752L, Texas Comptroller of Public Accounts, October 12, 2006)