Remote control does not operate the indoor unit; unit only responds to buttons on the front panel (if present).

Safety first: No high-voltage work is required for this issue.

Steps:

• Replace batteries: Install fresh, correct-type batteries in the remote control, observing polarity.
• Check line of sight: Ensure nothing blocks the IR path between the remote and the indoor unit's IR receiver window.
• Test remote: Point the remote at a smartphone camera and press a button; you should see the IR LED flash on the camera screen. If not, the remote is likely bad.

If remote is good: The IR receiver board in the indoor unit may have failed and should be replaced or the entire indoor PCB serviced by a technician.