Just a quick question. Recently, my POS Kenwood KDCMP632U head unit took a poo, so my friend gave me his old Pioneer P4600MP. The only things connected in the units wiring harness are ground, constant and switched, since I use the 2 pre-amp outs for my speakers and subs.

Took it for a ride today, and I have VERY LOUD alternator whine. The problem is, I did NOT have any in the kenwood unit, only after switching to the pioneer.

I used the cable end screw things to connect the three wires, as this was the way I had my kenwood hooked up, and never had a problem.

I'm assuming im making a ground loop? I might just solder the connections tonight and wrap'em in electrical tape.

Quick Update: Just unplugged my channel 1 and 2 RCA connection, and the whine went away, so its obviously before the amp. I switched around the rca cables, and its still doing it, so im definately sure its something with my head unit.

 

pioneers have had issues on some series with the rca outputs. Try taking an extra piece of wire, and connecting the outer portion of the rca to ground and see if that helps.

 

ttocs, I gotta say something man. I had at least 5 people give me advice on this, and I tried every single one of their ideas and nothing worked.

So I got bored tonight at work, and took the rcas out of the back of my head unit. The whine was there. So I stuck them on the frame. "No ****." The noise stopped.

Soon as I got home, I cut off the ground wire to the old wiring harness for the Kenwood head unit. Drilled a screw into the frame where I held the rcas before, and wrapped the wire around it and tightened it.

I put the other end in the female RCA on the head unit, and jammed the cable in. Fired it up. Complete silence. I was dumbstruck that this hugely annoying problem had such a simple fix.

You are, for lack of a better term, THE MAN!!!

 

ground loop isolator work good if u have rca's or ground your block to the body and alt to body

just saying hey so i can get my post up to 100 so i can post my 1/4 mile times

 

its a strange problem that has been known in the industry for some time. Glad I could help, your welcome and enjoy the tunes.....