Slide the point of a spudger under the speaker connector (just below the fan cable) and gently lift it straight up and out of the socket.

Don't lift on the cables themselves, or you may damage them.

During reassembly, hold the connector over its socket and press down gently with the flat end of a spudger until it clicks into place. If you're having trouble, don't try to force the connector into its socket—reposition it and try again.