When i retro fit a stereo the speaker would buzz, but when i put back the original Clarion stereo the buzz would stop, turns out there is feed back from the amp in the stereo and the amps in the doors, I did overcome this by fitting a blocking diode on each feed to the speakers, and this allowed me to use the new stereo on the old Range rover, it was fine for about 15 years but now it has started the buzz again, so suspect one of the blocking diodes that go to each speaker has failed
My P38 made the same noise. Removed the radio cleaned the connections, still had the noise. Didn’t have time to look any further. Came back to it two days later annnd no noise, everything working ok. What the hell, P38’s, got to love/hate them. Have a great Christmas. Hope you get it sorted. 🍻
To take the HVAC out you only need to take the side panels off. You do not need to take everything off. He took off. I know this because I just did it with mine yesterday.
The stereo noise may well be the amplifier in the l/h rear wing they do fail and make horrible noises in the speakers, I have 6 of these amplifiers they all have issues such as front speakers only work or rear only with interference and no one seems to be able to repair them
