Ignition OFF, disconnect the X3 harness connector at the MSM, Ignition ON, and verify that a test lamp illuminates between the B+ circuit terminal 5 and the ground. Ignition OFF, and connect the X3 harness connector at the MSM. Ignition ON, observe the scan tool Radio Driver Heated Seat Sw. parameter while pressing the driver heated seat switch. The readings should change between Inactive and Active. Observe the scan tool Radio Pass. Heated Seat Sw. parameter while pressing the passenger heated seat switch. The readings should change between Inactive and Active. If the scan tool readings are normal, there are no DTCs set, and the driver and/or passenger heated seat is inoperative, replace the MSM.