Arrived to do AC maintenance, checked thermostat for operation, checked and changed filter, checked temperature split, checked amp draw of blower motor. Checked compressor amp draw, checked condenser fan motor amp draw, checked refrigerant pressures. System is working correctly at this time. Found Reme Halo Bulb is still lighting but it is over two years old, the cell loses its efficiency and the cell needs to be replaced, per the manufacture.