Hi I have a 2004 Volvo S80 with a Unit 801 and my Rear Door speakers don't seem to be working only the front section and the rear subs working, I don't feel the rear door even vibrating. Any solutions guys? or something I got a check????

 

If there isnt sound and you dont feel sound vibrations then you have to possibilites. First and easiest is to make sure your fade is set right on your stereo. The other one is that they are dead or missing. I had the same thing on my car and it turned out that the speakers weren't even there and the wires were even cut.