Best place for an amp ground wire...
 

I need to redo my ground setup because when I added in my second amp I'm getting a squealing noise. I currently have them grounded to where the spare tire is suppose to screwed down to. I do have the paint scrapped off from there as well. Is there any easy way to run it down to the frame?

but that assembly the spare mounts is welded. I usually ground amps under the rear seat. be sure all the wires are the same gauge as well.

i grounded mine under the spair tire not to the spare tire hold down

That maybe it. My both of my amps grounds are the same but I have a aux plug in the back too and that is just a small ground. Do you think that could do it? I redid my ground and I will post pic of it later because its still doing it. Then you guys and tell me what I'm doing wrong.

an aux plug like a RCA adaptor?

no, a cigarette lighter. I had a power inverter for my tv in the back but I took it back out for now. But I left the plug back there

power inverters introduce noise. I have that issue with a i-pod aux adaptor I use.

well it started when I put the new amp in. I had the inverter before the amp and there was no problem.

noise can be pinched RCA, bad internal ground in the amp, outside electronics such as aux adaptors and such.