Can led tail lights cause static on the radio?
I bought some leds from these folks:
www.autolumination.com Tail Light Brake Light Turn Signal LED Bulbs
many have as we know. I got 3157 duel circuit red. It seems that when I hit the brakes and I get static on the rec nav radio stations. I understand this can also be the spark plugs or the alternator. I just don't understand what could cause the static on the radio, but it seems it started when I installed the tail/stop led lights.
I have LED tail lights and I've never experienced this.
AM radio? AM is much more prone to pick up RF hash from dirty switch contacts, alternators, spurious electrical noise.
Here's my theory: The LED lights do not load the system the same way as incandescent lamps, which act as a 'shock absorber' to the electrical current (the high initial current tapering off quickly as the filament heats up and goes high resistance - still can make noise though not as much). The solid state LED's just turn on and off, with a hard knee to the voltage / current load and no absorbing effect. This causes a sharp spike that emits RF hash, which AM radio picks up all day long.
Now if you're getting noise on the FM or the CD then the noise is actually feeding into your power circuits. Maybe putting a noise filter in line (choke and capacitor filter) with the brake light circuit would fix it, or a capacitor across the switch contacts. Most stock and aftermarket radios and amp have pretty hefty noise filters built in but you might add one to your head unit too.
Do you use a load resistor across the LED lamps? This would help damp the noise as well.
Die Hard Mopar fan~ '66 Chrysler Newport Sedan ('86-'93 RIP), '93 Eagle Vision (awesome car) ('93-'95), '95 Dodge Neon Sport Coupe ('95-'97), '97 Dodge Stratus ('97-'99),1968 Chrysler Town & Country Wagon ('95-'99), '66 Chrysler Newport Coupe ('99-'04), 66 Chrysler Newport Sedan ('04-present), 2004 Chrysler Pacifica AWD ('06-present - wifes car),
2005 Dodge Magnum RT (silver, tow package)
The noise is on FM radio only not on the CD. As for AM who listens to that anymore? Lol! I never listen to AM this I don't know if it's happening there.
Newport_66 I'm in no way a audio electric guy. I just plugged the led bulbs in and away I went: then noticed this static. It gets so bad at red lights the radio becomes useless. What kind of a capacitor should I get and where? Radio shack? I would need written directions with pictures to understand this. Lmao!
When I had the LED's in my tails in my magnum I never had the static.
Nick the spiders were on back order so I went with the towers:
some times yes, but only when you brake
All Uconnect Software
Yes!! The static is only when I brake.
Originally Posted by sox
I don't have this issue either and have led tails. You might try swapping out the led's for another manufacturer or pulling out one at a time to see if it's the left or the right side bulb or both. If its a single unit just replace that one. That's what I'd do first.
Some LED bulbs use a tiny driver circuit that operates at a high frequency just like a switching power supply or power inverter, these circuits usually employ a choke or some kind to filter out this noise. Try a different brand of LED bulb, these ones don't seem engineered well. You could try to filter out the noise by putting a capacitor directly across the brake light circuit at the bulb on both sides, but you'd have to cut and splice into your wiring harness and it would be a band-aid at best.
Also, as suggested above it might be that just one of the two brake lamps has a bad driver. Do as he suggested first and remove and replace them one at a time and see if it goes away.
Last edited by newport_66; 08-31-2012 at 01:10 AM.
yeah thats the issue is the bulbs. This was a company many used without issue.
Originally Posted by newport_66
Can someone direct me to a good led tail light bulb for the 3157? I have tinted tails and I need something bright with that center brake light. If not I'm going back to stock which will get me pulled over! Noooooooooooooooooo
What company did you get them from? Also you can try regrounding your radio to actual metal behind the radio.
Just the other day at work I had to reground a back up camera because when the brakes were applied it actually white washed the picture. The camera was grounded at the reverse light harness also and i guess there was too much draw on the ground circuit and thats why the picture had interferance.
You also could tap into your brake light ground wire and ground it right to the metal behind the light. Just remember to sand the surface down to metal where it is grounded.
Company was auto illumination on line. Many on here bought from them. That grounding sounds like a plan. Might try that. Both sides?
My neck question is it possible that it's a speed sensor? My right front the bolt was shears off some how so I sipped tied it for now till I get the screw that's broken out. Today UpInSmoke and I did my tie rides and I moved it a bit. Much less static. Almost gone.
Sounds like it could be at least part of it.. A bad ground or some wayward magnetic field can really screw our electronics up.
Do you get static when the car is not moving and you are on the brakes? If it's a wayward signal from the speed sensor it should go away after your car is stopped, but if it's because of some grounding issues with that sensor due to the missing screw, you may have the issue while it is stopped.
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