Evening all
Anyone know why I get interference on FM radio stations when i brake, figure it something conected to the brake lights coming on, anyone know why or if there is a quick fix. thanks in advance.

Has your car been fitted with aftermarket LED tail lights or the high level brake light? is there a smart bypass relay fitted for the towbar electrics?

LED bulb in the high level brake light and an aftermarket smart relay for the caravan socket in the passenger side boot side panel.

I would remove the LED from the brake light and re test, some LED units emit radio interference that will degrade radio reception.

HTH

regards Paul

(edit) some smart relays also cause noise but it tends to be most functions rather than just one. If you have a trailer with LED lights that can be a source of noise as well.

This is interesting. I fitted LED lights to my interior that’s footwell, both roof consoles and boot. I have noticed that sometimes when the front passenger door is opened the DAB radio cuts out until the door is closed again. I just put it down to a poor connection but the LED interference seems possible.

LED lights require the current flowing in them to be regulated, you can do this regulation in several ways but generally it’s done by turning the applied voltage on and off at a very fast rate, by changing the on off period (controlling the duty cycle) we control the heat dissipation in the diode junction.

Cheaper units do this with scant regard to controlling the rise time of the current pulses and the sharp edges of the waveform contain harmonics that extend well into the vhf and uhf radio spectrum.

HTH

Regards Paul

I had some MR16 12v LED downlights in the bathroom which are fed from an electronic transformer. I found that they zapped all FM reception in the house. Similar effect. PS don't buy cheap stuff off Chinese suppliers on Aliexpress.com 3 x FL1 2 manual + 1 auto
5 x FL2 4 manual + 1 auto
Now Discovery Sport P250 MHEV SE

I bought mine as a set from Powerful. They weren’t exactly cheap as I had read up on bulbs causing problems.