You can check the fan's capacitor and the fan's motor shaft & bearings. I'm surprised the breaker doesn't trip. I'm assuming all is well with the circuit if the compressor runs til it trips out on thermal overload but, it wouldn't be a bad idea to make sure you have 240VAC at the relay. I've had some luck reviving motors by nursing some light weight oil into the shaft bearings. However, your most likely looking at having to replace the fan motor. Only a diagnostics will tell for sure.