Car Talk: LED lights can interfere with radio signal

Dear Car Talk:

My husband installed LED lights in our 2012 Chevy Malibu LTZ. Since then, the radio signal has been awful. Even some of the 50,000-watt stations don’t come in very well anymore. My favorite radio station is mostly static, and cuts in and out so much that it makes me miserable. I have even taken to driving our 2002 Chevy Suburban with the crappy radio. He says it’s the station’s fault, but it started when he changed out the lights. What did he do, and what does he need to do to fix it? Any more misery on my part and I’m setting the flying monkeys on him. Can you help? — Kathy

Oh, it’s definitely your hubby’s fault, Kathy. But you already knew that.

I’m guessing that the power source for the cheap, poorly shielded LED lights your husband bought probably is creating some radio frequency interference that’s being picked up by the car’s radio antenna. The most surefire way to solve that is to rip out the LED lights and leave them on his side of the bed, with a note that says, “Hope you saved the old lights, Fred.”

But before you resort to that, he should try to find a dedicated car stereo shop that does nothing but install and upgrade automotive sound systems. Having dealt with their share of irate customers, I’m sure they’ll have some ideas about whether the offending parts can be successfully shielded, and if so, how.

We spoke to our car stereo go-to guy, Jim Cavanaugh of Sound in Motion in Boston. He agrees that the cheap LED kit is what’s causing the problem. He says your husband can try something called a CAN Bus, which is a filter you install between the car’s light connection and the headlight kit. It might help, but just as likely, it won’t. However, at only $20, it’s worth a shot.

When the CAN Bus doesn’t help, he’ll have to remove those cheap LEDs and either reinstall your old halogens, or invest in a higher-quality, properly shielded LED light kit. Jim says he’s had good success with LED kits from PIAA, Race Sport and Putco, if you want some suggestions.

In the meantime, you can keep driving the Suburban, Kathy, or look on Craigslist for a 1981 Sony Walkman. Good luck.

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