York outdoor fan runs but compressor does not start; loud humming then clicks off

Safety: Disconnect power at the outdoor disconnect. Capacitors can hold a charge—discharge safely before testing.

• Inspect capacitor: Look for bulging, leaking, or rust on the dual run capacitor in the York condensing unit. Replace if any signs of damage.
• Test capacitance: Use a meter to verify the µF rating matches the label within ±10%. Replace if out of range.
• Check compressor terminals: Ensure all wires are tight on C, R, and S terminals and that the terminal plug is not burned.
• Consider hard‑start kit: If the compressor is mechanically tight but not failed, adding a manufacturer‑approved hard‑start kit can help starting (technician recommended).
• If compressor still will not start: A technician should megger‑test the windings and determine if compressor replacement is required.