I have a 2001 convertible with a Mach 460 stereao. When I push the brake, I hear a pop through the speakers. When I'm at a light, with the car in neutral, I get a hum. I push in the clutch and the hum goes away. Pretty much the same syptoms with the FM and the CD player.

Anyone have advice on where I start to look for the source of the problem??

 

My 2000 convertible has the same problem, ever since the warrenty expired. Have you found a solution? One difference, I have an automatic, so I can't make the hum go away.

 

Not yet, but to be honest I havn't given it much effort yet. I find myself driving more with the stereo off to hear the sound of the engine and exhaust. I'm thinking it's a problem with one of the amps, because I can hear the hum for a few seconds after I turn the radio off. I'm looking for a factory service manual, with a good wiring diagram before I begin to poke around. I think e-bay may have one or two on DVD. If I find anything out, I'll be sure to let you know.

 

You may want to try changing the ground point of the amps that power the rear speakers. Maybe the convertible top motor is using the same ground or close to the ground of the rear amps and causing a ground loop.

 

i have a similar problem in my 01 convertible. Same things like you said, except when i blink to make a turn and such the humming sorta comes and goes with the blinking, it's very odd. I tried changing ground points, didn't help me out. I was told about a ground loop eliminator or something of this sort that radio shack sells, however the guy there told me they haven't carried those for years. Only difference is i have an aftermarket stereo.