I had a radio customer purchase LED headlights to the tune of $$$. Looked cool and really dressed up the nose of his rig. He fired up the truck, hit the headlights and his beautiful, big ass radio (yeah, I put it together for him) went berserk. The needle on the S meter almost pinned with a noise level +20 over and he couldn’t hear shit. It even covered up mud duck in the desert (thank god for some things). Turned the headlights off, and the noise went away.
Obviously, the headlights are the cause, but why? The LED headlights function by means of what is called Pulse Width Modulation, PWM. They turn on and off at a rate that the human eye perceives it as being constantly on, (so much for eye witnessing). The side effect of this rapid switching off and on creates EMI, electromagnetic interference, and since I’m a radio nurd, I like to call it RFI, radio frequency interference. Also, keep in mind that that anything that spins in a vehicle, wiper motor, blower motor, alternator, electric fan motor, all create RFI. Shitty radios pick up everything, but even very good ones can’t help but ram LED noise into your speaker.
Now I’m of the opinion that if you manufacture something that is causing the customer’s other equipment to malfunction, you as the maker should come up with the fix. They could hide behind the guise that they are not causing harmful radiation and are compliant with IEC 61000, CISPR 25, FCC part 15, blah, blah, blab…….. But bottom lining it here, they’re fukin with your radio. So, of course I contacted one 8 months ago, and contacted them again. Yeah kinda like calling a government office, you don’t hear nuttin. So now we have to come up with a possible solution.
I tried an old school trick that worked on a couple of trucks, but it’s not guaranteed. I take 8X coax and turn it into a power cord from the battery directly to the radio. If you want to see a video of it, check out an Instagram post I put up on the subject. An alternate method could be snap-on ferrite cores, but to work properly is going to take a lot of experimentation and splicing to get the full effect.