I was running my AC normally, and it suddenly stopped cooling. The display is just blinking "E7" and making a beeping sound. I tried turning it off with the remote and turning it back on, but the error won't go away. Does anyone know what this code means? Do I need to replace a part, or is there a way to reset it myself?

E7 is a "Communication Error" — basically, your indoor unit and outdoor unit have stopped talking to each other. Try these two things before calling anyone: The 10-Minute Reset: Turning it off with the remote doesn't cut the power. Turn off the main breaker switch for the AC. Leave it completely off for 10-15 minutes, then turn it back on. This clears the glitch almost half the time. Check for Chewed Wires: If the reset didn't work, inspect the main wire going to the outside unit. Rats and birds love chewing on these. If the wire is cut or loose, that’s your problem. If the wire looks fine and the reset didn't help, your outdoor PCB board might be fried from a voltage surge. You'll definitely need a tech for that.