Alternator whine with XM unit. Options

[Tom06]

Per my other thread, I recently installed a new headunit. Today I installed the XM unit that integrates with the stereo and allows control from the front. This is a great setup, but unfortunately there is a high pitched squeel in the background when the engine is working.

I'm guessing that this is due to a grounding issue?

I am aware of ground loop isolators, but the ones that I see work through 1/8 inch audio cables. This would not help me, since the XM tuner connects to my headunit through the bus link in the back. When installing the XM tuner, I had to connect a switched power wire, and a ground wire to my radio wiring harness.

Would it make the problem go away if I connect the XM ground wire to something metal on the car? If not, is there some sort of filter that I can install?

EDIT: After more research, I don't think the ground is the problem, since the headunit and XM unit are using the exactly same ground cable. I'm thinking using this on the power wire to the XM unit might work? http://www.myradiostore.com/noise-filters-...fiers/nf-5.html

[Tom06]

Actually It might be the tuner itself .

http://www.xmfan.com/viewtopic.php?t=85890...sc&start=15

[Tom06]

As info I soldered the noise filter in on Thursday and the problem is gone.

[streetfighterguy]

When i turn off my radio the sound goes away

But usually i just turn up the volume so the sound isn't noticed in the background

[Shadowhawk]

I had the same issue with my ipod jack... kind of weird it sounded like I had a s/c in my car at low rpm.

[Tom06]

Was this in a factory setup, or aftermarket?

[songee623]

Sounds like a grounding issue.

[Tom06]

My understanding is that continual background noise = ground issue. Noise that changes pitch with the engine = poor shielding on the component that allows the variance in power from the alternator to come through. My problem was #2.

[cw_52]

I have a 2010 Touring and my Xm is coming with alternator whine while obtaining its power from the cigarette lighter jack and using the AUX input on the radio. Various permutations provided the same result.. a whine which varied in pitch based on engine speed. I purchased a unit similar to the one described in a previous msg, but without resolution. I suspect that I may need to install a 40A ground loop closer to the battery. I have an Ipod, and will see if that gives same result in order to determine if it's just my xm skyfy3 or an alternator/electrical issue.

Regardless of this, if you go into the options and lower the line-out so no audio comes through, turn radio volume UP you will hear all kinds of 'interesting' things...FYI