Performed AC diagnostic on 2012 XC 21 Lennox condenser. Upon my diagnostic client stated the outdoor unit was not turning on and hot air was blowing out of supply vents. Upon further investigation found that the fuse had a hole blown through the bottom on it. Proceeded to also find that the duel secondary motor control was reading at 39 µF which is way below the specified reading of 45. High voltage relay also showed signs of pending on contact points which can lead to failure on start up if this increases and gets worse. Power disconnect was also not equipped with search protection in the case of a power outage thunderstorm etc. this may also cause the fuse to become blown. Upon inspecting the indoor unit I found the 5 inch thick Merv 16 filter was Has been in place since 2016. Filter was beyond restricted and clogged with dirt. This is choking the system off and reducing the efficiency heavily. Outdoor condenser coil’s are also covered in dog hair which is cutting systems Airflow