Turn off power to the AC unit at the thermostat, breaker, and disconnect switch
Verify power is off with a multimeter
Remove the access panel to reach the capacitor
Take a clear photo of the wiring before disconnecting anything
Discharge the capacitor safely using an insulated resistor or have a qualified technician do it
Note the capacitor’s microfarad rating and voltage rating
Buy an exact replacement with the same microfarad rating and equal or higher voltage rating
Label each wire terminal before removal
Disconnect the wires from the old capacitor
Remove the old capacitor from its mounting bracket or strap
Install the new capacitor in the same position
Reconnect each wire to the correct terminal
Tighten all connections securely
Reinstall the access panel
Restore power at the disconnect and breaker
Test the AC unit to confirm proper operation