My York-window type air conditioner Model YDUSC24-6R is giving me a hard time. I turned the unit on and after a few minutes or an hour, the cool indicator light will start blinking and the air from the unit will be warm. Do you think it needs freeon gas or it may be something in the front panel? If I hit the front panel a few times, the indicator light stops blinking and starts working... but then the indicator light starts blinking... What do you think is happening?