Performed clean and check on ac system checked filter which needs to be changed customer plans to replace this them selves checked humidifier pad which was clean and left new pad on site as it's already payed for customer believed mice may be getting into the house through the air handler inspected unit and found no evidence of rodent activity but did point out to the customer that it appears to be coming from a wall at the side of the furnace near exposed insulation. Checked temp drop tested and inspected all electrical components and controls rinsed and cleaned ac coil all operations are normal at this time.