Ok, so the problem is that i am getting some serious alternator sounding noise. I have tried 3 head units, 3 different amps. The noise only happens when the heater fans are going. If you switch it to the off position it disapears. There is no noise at all when u wire the speakers through the cd player itself, only when the speakers are hooked through and amplifier. Any suggestions.

'04 Nissan 350Z track edition..

 

How is your amp grounded?

 

I tried grounding in 4 different places on the chassis, even tried a solder ground

 

Chassis ground for an amp will give you alternator noise every time. You need to find a nearby wire-harness ground or run dedicated power/ground wires all the way to the battery.

When I installed my HU I found a nice harness ground back behind the triple gauges that bolted to the dash chassis as well. Mine is an '07, don't know if it exists for the '04.

OTOH, you might be able to get away with one of those cheap chinese rca ground loop isolator thingies.

 

it does it with the car not running at all only when heater motor is going

 

Heater motor / alternator, same thing. Chassis ground will give you noise.

 

Just tried going all the way to the battery, no difference at all,

 

I've installed 100s of stereo systems, and the majority included at least 1 amp. I've only had alternator noise a handful of times, and I've only grounded my amps at the battery on cars that have batteries in the trunk. Even then I didn't do it on every car. Also, I can't think of a single mass produced car that would have a ground wire big enough to support an amp, besides existing chassis grounds, in an OEM harness. Probably 1/2 of my noise issues were caused by faulty components, as well. If you're talking about head unit internal amps, then your advice makes sense but I still wouldn't say that you'll always get noise. Hyundai, Kia, and Mitsubishis are almost a guarantee for noise though.

OP, your noise could be from one of 2 things... A bad ground, or EMF. EMF is caused when a large power wire is run near signal wires. The wire creates an electromagnetic field (EMF), which is then picked up by the speaker wires.

-Has the system always done this, or did it work fine for a while and then start?

-Where are your RCA cables ran, and where are the power cables ran?

-Make sure your ground connection is A+. Make sure you've got a good connection between the wire and the ring terminal, as well as a good connection at the amp itself. Also, sand/Dremel/grind/file/chew/whatever ALL paint and surface coatings off of wherever you're bolting the ground to. The ground needs to have a clean metal to metal connection to the chassis, no exceptions. After you get the noise figured out, you can paint over the ground connection if you're worried about corrosion. Just do this AFTER the ground wire is solidly bolted down. I also hit the ring terminal itself with the Dremel on systems that are giving me trouble. Just to knock that glossy coating off.

-Are you using a Pioneer head unit or Pioneer amp, by chance?

-The noise is definitely coming from the speakers that are hooked to the amp, correct?

-The noise definitely ONLY happens when the A/C / Heater fan is on, correct?

 

this is the first time it happened to me to. ok now there is massive alternator noise when i start the car, i ran the amp and head unit directly to the battery, power is on left side of the car, signal cables are on left side, completly away from each other. if u want feel free to call me please
406-231-3465

 

ok so i ran a ground lead to the negative rca cable and it disapered
whats with that

 

Sounds like a bad ground on the internals of the amp itself, or bad RCA cables. That's why I asked if you were using Pioneer products, since their well known for that issue

If I were you, I'd return everything to how it was BEFORE you started trying to fix the problem. Then, run a ground to the RCAs like you have it right now. That should have you sorted out. You could try a new set of RCAs as well. If you pinched the RCAs bad enough, it can cause this issue.

Oh and there's not a negative and positive RCA cable. The negative on an RCA is the part the goes around the outside of the jack on your amp/head unit. So what I like to do is either solder a 20 AWG wire to the outside of the barrel and use that as a ground, or when diagnosing things I'll just wedge it between the jack and the barrel.

This link explains what I mean. You don't have to run the RCA ground to the headunit chassis. You can run it to any good ground. The link also has tons of info on why this happens. http://forum.realmofexcursion.com/he...rcas-pics.html

 

im not sure what it was or is but 3 different head units, 3 different amps, but i did the ground on the rca terminals on the head unit which is a jensen uv10 that i like but

PROBLEM SOLVED THANKS FOR ALL THE HELP VERY MUCH APPRECIATED!!!

 

I don't know if someone said this yet but if your power wire to you amp is running right along the RCA's to the amp u can get some engine noise. If it is try routing farther apart from each other. And make sure u have a solid ground on that amp. Better quality rca's and wire do make a difference

 

Sounds like you've got a pinched RCA wire. Your fix should last for a long time, but the ultimate solution would be to run new RCAs. If it were me, I'd leave it as-is until the summer is over. It's over 105 today and will be for the rest of the summer. ugh...

 

problem is eliminated tried 6 different sets of rca cables, 3 head units, and 3 amps. tried hooking up everything straight to battery, mabe something in the car itself not sure, so i did the solder trick on the barrel of the rca cables and everything is just fine, so now im runnin a JL 1000/1 for the front highs, JL 1000/1 rear highs and 2 JL 1000/1 for the 2 12s' in the hatch. Its now pure insanity.. Thanks for all the help u did offer....