jmpolyak said:
my 1999 Range Rover 4.0 S radio making a very loud buzz/humming noise when I start the engine. .
Something you said in your original post which may have been overlooked, at least by me: That the loud buzz/huuming noise begins when you atart your engine.
So here's my question; If you turn on your Ign, but not start the engine yet, does the radio sound OK, and the noise only appears once the engine is started?
If that's the case, it may lead one to look to an interference issue, rather than an audio system issue.The Bad Ground idea has some merit too, as it can be the link to an audio/engine interference problem.
The loud buzzing is a symptom that manifested itself in my son's '93 RRC, but primarily from only the RF door speaker. The car had the ADS audio system, and behind the speaker , inside the door panel, was some sort of network, which was supposed to be held in place with tape, or double sided sticky material (That is SO early Land Rover) The circuit board came loose and was ARCing on a piece of the door frame, sparks big time like it was a powered network. Anchored it back down and never heard from it again.
The flip side is the noise present even before starting the engine, then it's audio related only. If there is an open in a shielded cable from the CD deck (Do you have one) then that could do it, or any other AUX input.