LED fog lights causing constant CB radio static

[Viking Jeeper]

Try not to hate me but I have one of those huge chinese front bumpers (purchased almost two years ago) that came with built in fog lights as well as a light bar. I actually like it, considered going with something different when switching to the LJ but kept it. In the TJ I had my Cobra 75 CB powered by a fuse tap behind the glovebox. When I turned the fog lights on the CB radio emitted a constant loud static, making it unusable. After a little looking I saw recommendations to run power for radios directly to the battery, never did that in the TJ because I was hoping to sell it. Now I finally got around to installing the CB in the LJ (bumper was already moved over) and ran the power and ground wires for the CB directly to the battery. The CB still admits a loud, constant static noise when the LED fog lights are on. The fog lights are on the factory harness and switch. I have LED headlights and light bar that dont cause that noise. Any ideas on how I can correct this? I know I dont have to have the fog lights on when I'm using the CB but I like things to work.

 

[pagrey]

There probably isn't an easy way without getting new lights. Shielding noisy RF sources is a big headache. The one thing I would suggest is to test your CB with a buddy, it is very possible that with your squelch properly adjusted you wont notice the noise at all. Most of use just use these things for trail communication and the signal from a fellow Jeeper on the trail is so strong you can turn the squelch really high.

 

[Viking Jeeper]

I forgot to mention that adjusting squelch has no effect.

 

[wigsajumper]

Maybe try some of these on the headlight wireloom EDIT: I can not remember if you put the core on the wire you want to shield or the wire that is giving off RF sorry. It has been almost 14 years since I was in an electronics shop

Ferrite Cores. They can soak up some of the RF interference that cheaper LEDs give off.

https://www.amazon.com/dp/B01N0AV746/?tag=wranglerorg-20

 

[John Scoggins]

I do not know exactly how your LED's are wired but I would think there is a relay controlled with a switch. One way to help identify the source of the noise would be to disconnect the LED's from the jeeps power (from the relay), then run the power AND ground from a remote battery (or battery charger) not connected to the jeep at all.
Power on the LED's and see if there is still interference, if no interference then the LED's are crap and leaking RF through the wires.
If there is still interference, then unbolt them from the bumper, see if the interference stops, if it does then the LED's are crap and leaking through the body of the LED housing.
If there is still interference with the LED's on but not connected to the jeep at all then the LED's are crap and leaking RF all over the place.

 

[pagrey]

I forgot to mention that adjusting squelch has no effect.

If squelch has no effect when it's all the way up I think that means the radio is not picking up electrical noise from the antenna, it's getting it from the power wires and putting a single filter at the CB might work. It seems odd because most CBs I've seen have pretty good input power filters.

 

[Jerry Bransford]

Cheap LED lights can emit a shitpot full of electrical noise. A good-size electrolytic (polarized with + and - connections) capacitor between the + wire of the LED and a good solid ground connection might help. And if your bumper is heavily powder coated the LED lights may not be getting a good solid electrical ground through the bumper to the Jeep. Try running a temporary ground wire between the LED's negative ground wire and the - post of the battery or the ground connection on the engine block.