So here's a weird one. Heading home the other night and turned my headlights on and there is a loud noise, almost a buzz or squeal coming from the radio. If I turn the radio down the sound goes away with it. Its like there is a wire crossed or feedback coming through the radio. It starts with even just turning the running lights on, aka on click of the head switch. Any ideas?

 

this REALLY sounds like a grounding issue. I am not a car audio guru but I have experience with audio equipment in general and the beefier the system the better the grounds have to be to get rid of trickle static stuff. And our cars default grounding SUCKS. Start there I would .

 

That's a good idea.

 

Is this a stock radio?

 

Stock everything but the rear speakers. I have a small Chinese amp with 2 aftermarket speakers running in the rear. Grounding issue seems like the logical choice but it was running fine and this just all of the sudden happened. Its just weird how it is fine up until the headlights are turned on.

 

Are all the speakers outputing this whine? Fiddle with the ballance and fade. If its just the rears, its your amp ground. Does the amp have a neg. cable all the way to the battery?
If all speakers are whining, its most likely the stereo or possibly headlight grounds. Whatever the cause, it sounds like a ground loop problem.

 

If the noise increases with the engine rpm then the alternator is causing the noise when it is asked to produce more current. Grounding may very well solve this but the alternator may be developing a problem as it rectifies Ac to DC.

 

Did you run your power along the fuel pump behind the back seat?

 

Well the amp is a tiny tiny little thing that I actually ran off the power cables for the original speakers. Im going to try to ground it to the trunk frame and see what happens.

The sound is coming from the speakers because I can turn it down and the sound goes away. I have not tried fading it to see which ones, thats a great idea. Thanks guys! Ill post back when I find the solution.

 

Well, I tried fading, the sound is on all speakers. I also unplugged the power and ground from the rear speakers, basically eliminating the rear setup and the noise was still there. Grounding seems like the problem but where do I even begin??

 

Make sure your HU has a good ground to chassis. Remove it and check continuity from the plug to chassis ground. Check the ground on the circuits that introduce interference (ie: heater fan or headlights. If your alternator has a bad diode, any load will cause more electrical noise. You can have your alternator tested in the car by a real shop (not autozone) to check your diodes and all the components.

 

maybe its white noise, do you hear voices when this happens?

 

if you have hid's the ballasts might be sending out an interfering frequency that your radio antenna is picking up

 

Update:

Woooo I fixed it! Sort of.... It was raining today and the first time I have had to turn on my headlights for a while so I was dreading the trip to work with no radio. I relized that changing radio stations would eliminate the noise while it was swapping over and for some reason, I decided to adjust the illumination dimmer. That fixed it. As long as it is at 0-middle or full it is fine, any setting inbetween the "locking" of those settings causes the noise. THAT, I can deal with. Thanks for the ideas guys!

 

so the dimmer switch eh? the problem is still there, but you're deciding to live with it. That's fine, just remember not to lock the dimmer

sounds like a crossed or shorted wire or something going to the HU.

 

More likely a bad switch emmiting RF.