Loud Whiste/Hum/Electrical Noise

[Chafton10]

Hey guys, yesterday I had just gotten a 54 inch curved led lightbar installed with a simple toggle switch. After the install on the trip back home on the interstate, I was greeted with a very loud and annoying whistle/humm from the drivers side speakers. It wasn't like this before the lightbar install. And it creeps in about 45mph and gets drastically worse at higher speeds. It is not wind noise, it comes with static from the drivers side speakers. Any tips/dui help would be much appreciated as I do not feel like making the 50 minute drive back up town to fix maybe a simple issue. Any help would be appreciated.

[Brianibew]

Does the sound go away when the light bar is either on or off?

[newdude]

Grab some door edge molding.  Cut it to length to fit the back ribs on the light bar.  One strip alone you will see a big difference.  I'd put 2-4 strips or so. 

[Chafton10]

3 hours ago, Brianibew said:

Does the sound go away when the light bar is either on or off?

I haven't tested to see if turning it on/off changes the noise. As usually it's at 50mph+.

[Chafton10]

2 hours ago, newdude said:

Grab some door edge molding.  Cut it to length to fit the back ribs on the light bar.  One strip alone you will see a big difference.  I'd put 2-4 strips or so. 

You're saying that the back of the lightbar is causing my drivers side speakers to spew electrical noise? Ill try this out and see if it makes a difference. Appreciate your suggestion.

[newdude]

15 hours ago, Chafton10 said:

You're saying that the back of the lightbar is causing my drivers side speakers to spew electrical noise? Ill try this out and see if it makes a difference. Appreciate your suggestion.

 

Well...having re-read your original post...I see where you say its from the speakers.  The fact it didn't do it before the light bar though...its either electrical backfeed (would not be speed specific like your issue) or wind noise from the back of the light bar.  Where is the light bar mounted?  Roof? 

 

My suggestion was based off of experience from a Jeep Wrangler Unlimited that our dealer had lifted by Hi Cal Motorsports in PA.  Customer came to test drive it and the noise over 45mph got louder with speed just as you describe.  I did some quick research on some Wrangler forums, and found about the door edge molding trick.  The back fins on most of those light bars end up causing unwanted noise at highway speeds.  Must be the way the air flows over the light (flat face to the light), it distorts over the fins and causes it.  Even one piece across the center rib when we started to experiment made a huge difference.  We put two more on and the noise was 95% gone.  The door edge molding smooths out the airflow over the back of the light. 

[x219c]

If it’s getting louder with the RPM and not actually the speed, it’s definitely an electrical problem. Usually a ground loop or something of that nature. I would check the new grounds on what was installed. Maybe they just tapped an existing wire or something, which could cause this kind of interference.


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