I called Carrier tech support to help me confirm the exact cause of the unit freezing up. The defrost board is corrupt and it needs to be replaced along with the coil temperature sensor. There is no way to verify for sure the operation of the outdoor fan motor because it gets its voltage from the defrost board. I did verify that it had line voltage. The part is covered under warranty but the labor is not as the 2 year full warranty expired in early January. I spoke with the customer and Mr. Koehler will call the office if they decide to have the repair done. Also I let Donna know that the customer is expecting a call from the office for payment as I could not collect over the phone and previously this is how the customers paid for any invoices.