I was driving home and all of a suden my speakers started screeching some sort of siren sound. It was like a car alarm but inside of my truck coming from all the speakers. I pulled over and unplugged the RCA's from the amp and it stopped but no music of course. Now when i plug them back in while the truck is off but key on it emits a humming and clicking from all the speakers. As soon as the key goes to the next click and the air and everything else comes on the humming gets even louder.

The amp is grounded to my seat and when I move my power seat up or back the speakers react with different humming and crackling noises. No cables are crossed.

Does anybody know what this could be?

I have a DNX7100 head unit that still powers up and you can hear the music now behind the humming but the humming overpowers the music. The amp is a Power Acoustiks, I currently dont have subs hooked up so its just powering my surounds.

 

Did some more troubleshooting and when i actually start the engine the noise gets even louder, so its a quiet hum with the key one click, a louder hum and click with the key in the on position and a loud screechy hum with the engine started. Seems like the more juice the battery puts out the worse it gets.

The only thing I changed today before it started was i moved the seat forwards and back to clean under it, but then i listened to the radio for like 30 minutes while driving to lunch and it randomly started with the super siren squelch on the way home from lunch.

 

Further tinkering reveals that the humming stays the same volume no matter what I so with the radio volume, so i can drown it out with loud music when the truck isnt on but with the truck on the humming is loud enough that it can still be heard with loud music.

 

Could it be the ground to the head unit? Not sure what would have changed it but just trying to isolate the problem. Its driving me crazy.

 

From morer reading I'm thinking I might need a ground loop isolator. Not sure why it came out of nowhere all of a sudden but does that sound like it would help? The sound is deffinately related to rpms so I'm guessing some kind of alternator interfernce.

Anybody have any advice suggestions, I feel like I'm talking to myself