i need help my back speakers wont work

my back speakers wont work after hookin up my new cd player.

could it be the factory amp that is in the car?

help me out :smiley:

Do you have premium sound in the car?

If so. There is a write-up on TeamZx2 because you need to do something to the AMP under the driver seat. I can’t remeber exactly but at least I know you need to do it.