Popping sound/alt whine through speakers

[Codym42]

I installed a 5 channel amp a few months ago along with a subwoofer. It works great but I'm getting a popping sound whenever I press the brake pedal. It's a very slight pop and, if I'm driving, I can hear a bit of alternator whine if I keep the pedal pushed in. There is no noise at all without the brake pedal pushed in.

Pioneer deh-p5200hd
Planet Audio 5 channel amp
Scosche RCAs run down left side of the car

If I unplug the headunit and plug in my mp3 player directly to the amp, there is no noise. So, I've narrowed down the issue to the headunit/RCAs. Also, I tried the trick of grounding the rca outputs on the headunit to its chassis and that made no difference.

Edit: It can't be the RCAs either because I just pulled the rcas directly from the headunit and played my phone through the amp. NO noises. That means something is wrong with the headunit...

Any help is appreciated. Thanks

[StereoInstaller1]

It's actually pretty common on pioneer decks, just a little surge will pop the Pico fuses on the outputs.

Do you have a weird noise between tracks on CD, even with the engine off? If so, it's for sure a bad deck

[Mr. Tasty]

engine to chassis ground or the hood ground seem to cause interference with radios and such.

[Codym42]

It's actually pretty common on pioneer decks, just a little surge will pop the Pico fuses on the outputs.

Do you have a weird noise between tracks on CD, even with the engine off? If so, it's for sure a bad deck

Luke,

No weird noises in between tracks just some slight static from the amp. The noise only happens when I push in the brake pedal.

I thought that if I ground the RCA outputs to the deck, that bypasses the pico fuse. I tried that and nothing happens. Maybe just a bad deck?

engine to chassis ground or the hood ground seem to cause interference with radios and such.

Both ground wires are still intact.

[Silver Wagon]

ground the deck and amp at the same point.
run a small gauge wire from your deck to the point the amp is grounded. you can do this with the wire not tucked away to test it. if this fixes the issue, then hide the wire.
your RCA's might have a ground wire built into them. its a small wire that most people mistake for a remote wire. although it can also be used for that.

edit, just saw the last post date. i assume all is fixed by now. my bad.

[Codym42]

ground the deck and amp at the same point.
run a small gauge wire from your deck to the point the amp is grounded. you can do this with the wire not tucked away to test it. if this fixes the issue, then hide the wire.
your RCA's might have a ground wire built into them. its a small wire that most people mistake for a remote wire. although it can also be used for that.

edit, just saw the last post date. i assume all is fixed by now. my bad.

I haven't had time to work on it lately but it still makes the sound with the brake pedal. I'll definitely try to ground the deck and amp at the same spot. I also want to swap decks and see if the noise goes away.

Hopefully I can test this over the weekend.

[dlmrun2002]

The brake pedal has a switch on it that makes contact and goes to ground. Try cleaning that..possible poor ground potential there.

dlm ny country

[Codym42]

I finally got time to work on this again. I put in a new brake switch, new Jvc head unit, and I tried grounding it to the amp. The problem still persists...

Sent from my XT1058 using Tapatalk

[Codym42]

Anybody know where the brake lights ground to the chassis?

Sent from my XT1058 using Tapatalk