Audio Systems: noise through power cable, 2007 gmc sierra, gmc sierra

Question
i'm trying to install a mono block amp in a 2007 gmc sierra.  When the vehicle is running without the rca's plugged into the amp, there is a lot of noise produced through my subs. A sort of constant humming.  Pressing the accelerator not not change the sound.  Pressing the brakes makes them thump over the humming.  I have tried 3 seperate ground locations including to the battery's ground itself.  The power cable is straight off the battery.  I have had the amp tested and it checks out.  Any suggestions?

Answer
there is nothing wrong with the amplifier
the problem is the vehicle  most of the radio wires send  audio and data
there hi low interface made for gm vehicles only you have to find one of them
also  check the battery ground to chassis and where is the remote coming from ? need be  from the radio only
good luck