No radio fade adjustment, No rear speakr sound
 

I purchased an almost brand new 2013 E350 Super Duty XL a few months back. Only has 14,000 miles on it and I was installing a DVD player for the kids this weekend. They say they can never hear anything in the back so I am back there and sure enough, none of the rear speakers are on. I still have the stock radio, which has the bass, treble, and balance adjustment but there is no option for "fade" front to rear that comes up on the radio. I verified there is speakers wired in, but why is there no fade option on the radio and I have no sound in the back?
Had anyone seen this before? Any help would be appreciated.
Tristan

Welcome to the site

Rear speaker control comes through the ACM (audio control module)
If your van is configured with anything other than the Base audio, the system can be scanned/diagnosed with a capable tool.
Could be there's a DTC or fault code stored, possibly a hardware issue