Upon arrival customer told me the thermostat is off and the outdoor unit was still running. I pulled thermostat off the wall to kill the 24 volts. The outdoor unit was still running and there is no 24 volt to the contactor. Found a contactor that was stuck on. I tapped the contactor and unit shut off. I replaced the contactor under warranty. Mention to customer to keep the unit off t8ll tomorrow because the unit is frozen good.