Rear speakers not working

Hey.

Had my car in the garage for an engine issue, but on the diagnostic report I noticed some fault code for the radio:

C919 Fault in left rear audio output -- Open circuit
C91A fault in right rear audio output -- Open circuit ​

Sure enough, on the radio controls if I put the balance all the way to the rear, no audio is heard.

Where would you suggest I start trying to fix this? Thanks.

 

Check the speakers themselves, the connector to them, first.

 

Hello bro,
I have same problem with my 407 Peugeot 2009, any help??