My first guess is the fan motor. If the capacitor or windings failed while running, it could have tripped the breaker. Now with the capacitor or windings open, there is no short to trip the breaker and the thud you hear is the compressor starting. Just a guess. You really have to go up top to see whats working or not
2019 Horizon 42Q Maxum Chassis w/tag
Cummins L-9 450 HP / Allison 3000
2006 Jeep TJ and 2011 Chevy Traverse Tows