Upper rear end panel inner panelling - see operation "Upper Rear End Panel Inner Panelling, Remove and Install" in group "C". Detach wiring harness plug from loudspeaker, holding something against it to avoid breaking off the connections.
Loosen 4 bolts and remove loudspeaker.
Install, Connect
Insert loudspeaker in upper rear end panel and fasten, connect wiring harness plug, install upper rear end inner panelling.
Remove, Disconnect 
Install, Connect 