Firstly I'm an hvac journeyman. You need to have a set of gauges hooked up to the ports to see what the operating pressures are while operating the ac. Off the top of my head I would say its stopping on high pressure safety because the fan is not operating. For testing only while the ac is turned on, mist the condenser with water to cool it off. If the ac keeps working then you know it was stopping due to the fan not operating.