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This question may have been answered, but couldn't find one. I installed LED's in my tail lights (C5) and now get static in some FM stations when brakes are applied or when right hand signal is on. No problem with left side so I assume since the Right side are so close to antenna that is were the EMI/RFI is from those bulbs. Is anybody out there using any particular brand of bulb that are shielded. These bulbs aren't cheap, they are EAGLE EYE SMD. Would CREE be a better bulb or is the interference something I have to live with. Any suggestions would be welcomed. THANKS
You are right, this interference is due to the PWM (Pulse Width Modulation) circuit in the LED bulbs which is being picked up by the radio through the wiring.
To solve this problem install a clip-on ferrite core right before each socket where you have those LED units installed. Install the ferrite cores as close as possible to the sockets.
Do it by putting the wires through the core and looping them back around it and going through the core again. These ferrite cores are widely used to suppress RF noise/interference.
Be sure to select the right inside diameter to allow looping the cables through the cores.
If making a loop is impossible because there is not enough slack in the harnesses, use a cable tie around the wires just before and after the ferrite core to keep it in place as close to the bulb socket as possible. The inductance will be lower, but you could try using two back-to-back cores to increase the blocking effect, as inductors in series are added up.
Yikes! Something else to worry about when installing LEDs. I was still trying to decide whether I wanted to switch to them and learning about hyperflash and other electrical anomalies that could be caused by LEDs. Now this? Hmmmm, I think I will stick with conventional lighting for the time being and allow the LED technology to improve a little more.
You are right, this interference is due to the PWM (Pulse Width Modulation) circuit in the LED bulbs which is being picked up by the radio through the wiring.
To solve this problem install a clip-on ferrite core right before each socket where you have those LED units installed. Install the ferrite cores as close as possible to the sockets.
Do it by putting the wires through the core and looping them back around it and going through the core again. These ferrite cores are widely used to suppress RF noise/interference.
Be sure to select the right inside diameter to allow looping the cables through the cores.
If making a loop is impossible because there is not enough slack in the harnesses, use a cable tie around the wires just before and after the ferrite core to keep it in place as close to the bulb socket as possible. The inductance will be lower, but you could try using two back-to-back cores to increase the blocking effect, as inductors in series are added up.
THANKS GCG, I'll try it. I saw these through a google search but didn't know if they were used on antenna wire or light wires. I also know that these are attached to my tv. I'll give them a try and post results. I wonder why the people selling led don't mention that there my be interference and sell these like they do with hyperflash resistors. Anyway THANKS AGAIN
...I even had a bit of extra lead length on the wires to loop them around for another pass through.
If you were able to make 2 loops the ferrite cores were probably too small.
Another possibility is that the ferrite material was not the right one for VHF. The appropriate ones for this application need to have a frequency range of 1 MHz to 300 MHz
You are right, this interference is due to the PWM (Pulse Width Modulation) circuit in the LED bulbs which is being picked up by the radio through the wiring.
To solve this problem install a clip-on ferrite core right before each socket where you have those LED units installed. Install the ferrite cores as close as possible to the sockets.
Do it by putting the wires through the core and looping them back around it and going through the core again. These ferrite cores are widely used to suppress RF noise/interference.
Be sure to select the right inside diameter to allow looping the cables through the cores.
If making a loop is impossible because there is not enough slack in the harnesses, use a cable tie around the wires just before and after the ferrite core to keep it in place as close to the bulb socket as possible. The inductance will be lower, but you could try using two back-to-back cores to increase the blocking effect, as inductors in series are added up.
Do you recommend attaching them to the (high) power wire or ground wire? Would there be any advantage to installing them on power and ground? Of all 3 wires?
I'm having this issue on C6 corvettes and found that installing a bead on the antenna wire helps. This would only apply to C5 verts and FRCs with the external antenna. Coupes typically don't have as much or a problem.
Do you recommend attaching them to the (high) power wire or ground wire? Would there be any advantage to installing them on power and ground? Of all 3 wires?
I'm having this issue on C6 corvettes and found that installing a bead on the antenna wire helps. This would only apply to C5 verts and FRCs with the external antenna. Coupes typically don't have as much or a problem.
Loop all 3 wires through each core as close as possible to the socket and do this to all "offending" LED bulbs.
What happens is that the wires act as an antenna for the RF noise and if you don't loop the 3 of them through the core the noise has a way out. That's also the reason for placing the core as close as possible to the socket: to minimize the effective length of the "antenna" between the socket and the ferrite core.
It is also important to use ferrite cores rated for 1 MHz - 300 MHz. We need to block noise in the VHF band.
Installing a ferrite core to the antenna wire is helping because it introduces attenuation, but it is attenuating the signal along with the noise. It is better to block the noise at the source.
Loop all 3 wires through each core as close as possible to the socket and do this to all "offending" LED bulbs.
What happens is that the wires act as an antenna for the RF noise and if you don't loop the 3 of them through the core the noise has a way out. That's also the reason for placing the core as close as possible to the socket: to minimize the effective length of the "antenna" between the socket and the ferrite core.
It is also important to use ferrite cores rated for 1 MHz - 300 MHz. We need to block noise in the VHF band.
Installing a ferrite core to the antenna wire is helping because it introduces attenuation, but it is attenuating the signal along with the noise. It is better to block the noise at the source.
Interesting....I will do some tinkering with this idea.
Will this work for a backup camera? I get interference from my sub amp on my add-on backup camera. Goes away when the radio is off.
Phil
So you're saying your sub amp is interfering with your backup camera? How does the interference manifest? "Snow" (noise) in the image?
You say it goes away when the radio is off, but don't you have to have it on to see the backup camera image on the head unit's screen? I'm a little confused...
I was going to suggest a wrap of metal kitchen foil to block the stray signals, but only because it is cheap and handy, don't know how effective it might be.
However the ferrite core suggestion seems as though it has actually solved the problem and is not just a guess .
Any more almost as good suggestions needed, let me know.
Sorry I misspoke. The radio is not off; the sub amp is off. It manifests itself in diagonal lies across the screen. I have tried wrapping the wires in kitchen foil but it did not work.
Must be a vert or FRC/Z06 problem since I have LED Halo taillights and a few other LED lights installed and no such radio interference.
Yes, the coupé shouldn't suffer from this problem, or at least not that much, because its antenna is embedded in the windshield and much farther from the tail lights.
Sorry I misspoke. The radio is not off; the sub amp is off. It manifests itself in diagonal lies across the screen. I have tried wrapping the wires in kitchen foil but it did not work.
Phil
How close is your sub amp to the rear camera? It seems that your amp's switching power supply is creating the interference.
The amp is mounted at the very back of the cargo compartment, vertically on the interior trim panel. The camera is on the license plate frame, so they are less than a foot apart.
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No worries... at least this problem can be easily solved with some inexpensive ferrite cores. With around $5 you can get a bunch of them! 
C5 led tail lights & fm static
