I recently just purchased a 2014 Chevy Malibu and there doesn't seem to be any sound coming out of the rear deck pioneer speakers. I did switch the balance to all on the rear speakers and all I am getting is sound out of the rear door speakers. I do feel a vibration coming from the speakers. Any idea what is wrong?

 

Is this a factory radio? Sounds like the Pioneer speakers are add ons. Check to see if the speakers are good. Try known good speakers as a test to see if they work. This will let you know if it is the speakers or not.

 

If they're aftermarket, probably with what you post, wrong pigtail connector.