Remote control does not operate the Haier air conditioner; no response from indoor unit.

Safety first: No electrical hazard for basic checks; do not open the indoor PCB without isolating power.

• Replace batteries: Install fresh, correctly oriented batteries in the remote.
• Check IR signal: Point the remote at a smartphone camera and press a button; you should see a flashing light on the remote's IR LED through the camera.
• Clear line of sight: Ensure nothing blocks the IR window on the indoor unit and clean it with a soft cloth.
• Test with another remote: If available, test with a compatible Haier remote. If the unit responds, replace the original remote. If not, the indoor IR receiver board may need replacement.