when i plug my pioneer head unit in, all my components work normally except the front left. When i turn the volume up a little the front left would pop then little sound comes out. I could barely hear anything. When i plug the stock HU in everything works perfect. I check the wiring of the harness and it look ok, i just match the colors to each other. pls help

 

What components are they?
So do they play as long as u dont turn it up.Or are they not playin at all now?

 

mb quartz rce, only when i turn the volume up on the pioneer deck that it does this.

 

Might be the left channel messed up on the radio,is this a brand new radio?
Try a different channel like rear right or somethin and see what happens.