Arrived to do a performance maintenance. Set system for cooling. Measured the systems static pressure measured a temperature split between return and supply air. Checked interior of the furnace for cleanliness. Made adjustments to the filter slot to make it easier to change and so air will not be bypassing the filter. Went outside and verified refrigerant levels. Verified operation of all electronic and mechanical components. Found a mouse nest in the electrical cabinet. Checked all wires for damage and sealed the protrusion to keep critters out. Rinsed coil free of debris. Spoke with homeowner about the system. Air conditioning system is operational at this time.