Tech arrived on site. Performed fall tune up. Inspected ignition components. Unit is 21 years old. Flame sensor is oxidized, and hot surface igniter has high readings. Both still operational. Inducer motor is okay. Blower motor is over amping and will fail. Pulled blower motor to inspect heat exchanger. Temp rise and static are okay. Heat exchanger is not cracked at this time. Hot spots on heat exchanger. No secondary drain pan on condensate line. Talked about replacement options as well as repair options. Unit is operational upon departure.