RR99i

Hi everyone! What I'm trying to do is, instead of wiring my car stereo straight to the battery. I'm wanting to figure out if someone knows this. How do you rewire that constant wire in my car? Basically from where it connects to the wire on the back of the stereo to where ever it may go. Pretty much fully rewire the constant wire. I was told you need to take out the dash and so on. It seems my constant wire for my stereo isn't putting out enough voltage for it. My switched/ignition wire must be, because that's the only way to keep my stereo from kicking off from high volume.

Any information that would help me solve this problem myself, would be great. I don't want to have to take it to a Car Audio shop.