Volvo xc40 amplifier

[Lukas]

I bought another amplifier from the xc40.  it worked on 5 channels, i.e. front and rear speakers.  when I installed it in my xc40, there is only sound in the front door.  configuration028 changed to high performance.  from how many 4th and 5th completely weak sound can't even be heard.  I don't know what else to try.  I still don't have speakers in the back door.  I will try it only through the connector.  connect an external speaker.