13 replies to this topic

[NJDirtyBird7]

Today I had an after-market head-unit installed (previously had an alpine aftermarket head unit)  in my car.  So basically the issue i'm having is that I am getting a hum sound from my speakers only when I turn on my headlights, even when I turn my speaker volume to 0.  I have an aftermarket stereo system, JVC head-unit, infiniti speakers, alpine 4 channel amp for my speakers, kicker subwoofer, and rocksford fosgate mono amp for my subwoofer.  I googled the issue and everybody seems to be saying it is a ground problem.  Not quite sure how to fix this as I did not do the install myself.  I was hoping that maybe somebody on these boards would know how to fix this problem. Please help!!!

[NJDirtyBird7]

Hairline, on 14 April 2012 - 09:58 PM, said:

Bad ground.

Very detailed post lol, i understand this.  Now how do I fix it?

[JDaveG]

It really is hard to say without knowing more.  One noise issue I used to see a lot is when the speaker wires are run alongside the power wires, but that's more of an amplifier problem than a head unit problem and it would usually be a problem all the time, not just when the headlights are on.  I'm assuming the unit you replaced had no such issues, which leads me to agree with Hairline that it's probably a loose connection grounding or shorting somewhere.

One thing to consider -- does the present head unit have any connections or features (that require connections) the old one did not?

Also, who did the install?  If it was a professional install, take it back and make them fix it.  If it was a buddy, get him over and ask some questions about exactly what he did so you can troubleshoot.  For example, most head units have a remote turn on so that you have 1 main power wire and another that activates the head unit when the ignition is turned on, so the head unit doesn't stay on all the time.  If either of those was wired to a different power source than the old head unit, that may be part of the issue.  Etc.  It's really trial and error at this point.

[NJDirtyBird7]

JDaveG, on 15 April 2012 - 07:32 AM, said:

It really is hard to say without knowing more.  One noise issue I used to see a lot is when the speaker wires are run alongside the power wires, but that's more of an amplifier problem than a head unit problem and it would usually be a problem all the time, not just when the headlights are on.  I'm assuming the unit you replaced had no such issues, which leads me to agree with Hairline that it's probably a loose connection grounding or shorting somewhere.

One thing to consider -- does the present head unit have any connections or features (that require connections) the old one did not?

Also, who did the install?  If it was a professional install, take it back and make them fix it.  If it was a buddy, get him over and ask some questions about exactly what he did so you can troubleshoot.  For example, most head units have a remote turn on so that you have 1 main power wire and another that activates the head unit when the ignition is turned on, so the head unit doesn't stay on all the time.  If either of those was wired to a different power source than the old head unit, that may be part of the issue.  Etc.  It's really trial and error at this point.

Well my amp was working fine right before the install, so I do not think it is that.  The new head unit does have many more features and connections than my old one such as navigation, HD radio, BT, and more front inputs.  It was a professional install, and they will fix it for free. I was just hoping I could quick fix it myself, but by your comments it doesn't sound like it.  Alright sounds like I'll just talk to them and have them fix it,  Cause I wouldn't know the first thing to do having to do with the ground or where that even is lol.

[JDaveG]

NJDirtyBird7, on 15 April 2012 - 03:20 PM, said:

Well my amp was working fine right before the install, so I do not think it is that.  The new head unit does have many more features and connections than my old one such as navigation, HD radio, BT, and more front inputs.  It was a professional install, and they will fix it for free. I was just hoping I could quick fix it myself, but by your comments it doesn't sound like it.  Alright sounds like I'll just talk to them and have them fix it,  Cause I wouldn't know the first thing to do having to do with the ground or where that even is lol.

My guess is they created a ground loop with one of the new connections.  I'd let them figure it out.  I know it's a pain, but it's probably not an easy fix.  A lot of trial and error involved.

[NJDirtyBird7]

JDaveG, on 15 April 2012 - 03:27 PM, said:

My guess is they created a ground loop with one of the new connections.  I'd let them figure it out.  I know it's a pain, but it's probably not an easy fix.  A lot of trial and error involved.

I don't have a problem with trial and error, I can do that.  But I don't have a clue where to look on the car for the problem.  Do I have to get behind the radio or could the issue be under the hood?

[JDaveG]

NJDirtyBird7, on 15 April 2012 - 03:38 PM, said:

I don't have a problem with trial and error, I can do that.  But I don't have a clue where to look on the car for the problem.  Do I have to get behind the radio or could the issue be under the hood?

It's all a guess, but my guess is you'd have to pull the head unit and check every connection -- I doubt the problem is under the hood (though it could be theoretically).  If they didn't install a new amp, I'd be surprised if they even opened the hood.  One way to shortcut it would be if the installer wired in a harness rather than cutting and crimping every single connection.  If they wired in a harness, you can first look to any connections that aren't on the harness (i.e., any connection that is wired to something else on the car besides the wiring harness).  Reason being anything in the factory wiring harness was probably working correctly before.  If they didn't, you'd literally have to check each and every connection.  Even if they did, it might be that when he wired the harness to the head unit, there's a shorted connection or a ground loop inherent in the harness, etc.

So it might be as simple as "there's this antenna connection or this power-on connection or whatever, and they wired it to this or that source, and I'm going to try another source," or it might be as complicated as literally going one at a time and figuring out which connections are wired the same as the previous head unit and which ones are different, or it might be worse than all that and you literally have to run down each connection separately.

[NJDirtyBird7]

thanks alot everybody for the help, gonna give it a shot tomorrow.

[capologist]

Honestly, I'd suggest taking it back to the installer because if you tinker with it and do not succeed and then decide to take it to them, chances are they will not work on it if they know someone else already has.

[NJDirtyBird7]

capologist, on 16 April 2012 - 06:40 AM, said:

Honestly, I'd suggest taking it back to the installer because if you tinker with it and do not succeed and then decide to take it to them, chances are they will not work on it if they know someone else already has.

You make a valid point sir, off to the installers it is.

[NJDirtyBird7]

Dojo Blaster, on 16 April 2012 - 12:12 PM, said:

hah

btw dojo, way to add useful and intelligent information to this conversation.  Muchos Gracias

[NJDirtyBird7]

Update:

Thank you for all the help people, I brought my car back to where it was installed.  They diagnosed and fixed the problem with no charge.  I was getting a hum just from my subwoofer, it was constant and went louder when other devices were turned on (lights, windshield wipers, etc.).  The problem was that the head unit I purchased has a mono sub woofer out and my subwoofer amp has stereo rca inputs.  So all the installer did was unplug one of the RCA's that was not even doing anything out of the subwoofer amp.  Now my system works great!

[JDaveG]

NJDirtyBird7, on 19 April 2012 - 10:17 AM, said:

Update:

Thank you for all the help people, I brought my car back to where it was installed.  They diagnosed and fixed the problem with no charge.  I was getting a hum just from my subwoofer, it was constant and went louder when other devices were turned on (lights, windshield wipers, etc.).  The problem was that the head unit I purchased has a mono sub woofer out and my subwoofer amp has stereo rca inputs.  So all the installer did was unplug one of the RCA's that was not even doing anything out of the subwoofer amp.  Now my system works great!

You don't need stereo for a sub anyway, so that sounds like a perfect fix.

[capologist]

NJDirtyBird7, on 19 April 2012 - 10:17 AM, said:

Update:

Thank you for all the help people, I brought my car back to where it was installed.  They diagnosed and fixed the problem with no charge.  I was getting a hum just from my subwoofer, it was constant and went louder when other devices were turned on (lights, windshield wipers, etc.).  The problem was that the head unit I purchased has a mono sub woofer out and my subwoofer amp has stereo rca inputs.  So all the installer did was unplug one of the RCA's that was not even doing anything out of the subwoofer amp.  Now my system works great!

Glad to hear it was easy and painless!