Radio Noise. Not running any amps.

Hi, I installed a Pioneer radio in my truck using metra harness that plugs in to the factory harness and wired it together to the pioneer harness. I'm not running any external amplifiers and I'm using stock speakers, truck does not have stock amplifier either. At 0 volume I can hear a very low whine/static:

1) It does not go up with RPMs.
2) It pauses for less than a second when I turn on the headlights, or when I first touch the gas pedal.
3) It only does it with the engine running.
4) Disconnected, antenna, usb cable, etc etc, and it still made the sound.
5) Does it regardless if I'm listening to CD, USB, or FM, AM.

I've search around the forum but most topics are related to those running external amps and running RCA cables to the amplifiers. My questions are:

1) Since it does not go up with RPMs is it still alternator noise?
2) I'm guessing I should start troubleshooting with the Radio ground wire, grounding it somewhere else. Anyone knows a good ground point close to the radio in a 05-09 Tacoma?
3) I know ground loops isolators affect sound due to being connected to the RCA cables, but will a Noise Filter in the radio 12V wire affect the sound quality?
4) Can using the Radio while it has this whine/static damage it?

Thank You for your assistance.

 

i would put the ground to the metal bar behind the radio and see if that fixes it.

sounds like a ground issue to me.

 

Thanks for the reply,

how would you attach it to the metal bar?

 

crimp a ring terminal to the ground wire.. then screw it to there.. if you dont have the tools to do that then take it to an audio shop.

of that doesnt fix it then you need a new head unit.