I have a 2004 1500 Laramie with infinity removed stock and fitted a aftermarket single din radio unit the harness i fitted powers up etc but no sound , if I look at the harness from truck there is only 4 wires compared to my 8 speaker wires.
Do I need to connect anything more to get sound , I have tried searching and all I seem to find is the same harness or a massive harness to bypass the the amp , I’m sure a few years ago I managed to fit a new radio and speakers worked but cannot remember how I did this , any diagrams , links etc much appreciated.
haynes manual only has the diagrams for the standard equipped stereo

 

The aftermarket head unit should have an ACC or Aux power wire, I believe its usually a blue wire IIRC. This should be hooked to the power wire for the infinity amp. Best to find a wiring schematic for the harness. The stock Radio should've had two connectors also if IIRC two sets of speakers in each connector along with other necessary wiring

 

Contacted Crutchfield, they were going to sell an amp bypass and new speakers that would lead to a lot of work. I researched the options and I connected the BLUE to the RED wire that powered the infinity amp. It worked!