I had a 2007 ram now got a 2008 meg cab try to use harness I made for 2007 for after market stereo which fine but new truck I get no sound put back stock radio works ok ,truck has no amp .help ??/

 

Welcome to DF I'll move your post to the appropriate section, they will be more than happy to help you.

 

MY best guess from what I can kinda sorta read is that you took the harness you made for your 2007 and put it in your 2008? Is that right?

Now if your 2008 has the infinity system this is when I would expect to see this problem....

Other causes are if your ground or 12V+ Ignition wires don't have a good connection.

You said you didn't have an amp, so I am guessing that means you don't have the infinity system, but if you have 7 speakers in there you definitely have the infinity system and you'll need the amp integration harness/CAN BUS Adapter.