DIAGNOSIS Remote control failure is either a faulty remote, a blocked IR sensor on the unit, or a problem with the unit's control panel not receiving signals.
FIX First, test the remote. Use the camera on your smartphone. Point the remote's LED at the phone camera and press any button. You should see a purple light flash on the phone screen. No light means the remote is dead. If the remote works, check the IR receiver window on the front of the AC unit. It is a small, dark plastic panel. Clean it with a dry cloth. Ensure no objects are blocking the line of sight. Stand within 16 feet and point the remote directly at it.
IF THAT DIDN'T WORK The unit's internal IR receiver may be disconnected or faulty. You can operate all functions manually from the control panel on the unit. If the buttons on the unit itself are also unresponsive, the issue is with the main control board, not the remote.
HEADS UP Aftermarket universal remotes are rarely fully compatible with this model's functions, especially timer and mode settings. A replacement OEM remote (model RAY12) is the only reliable option.