i have a 97 accord and not too long after the timing belt was replaced the radio began to buzz.
this happens when the ignition switch is on and gets louder when the headlights are turned on. turning the engine on has no effect on the buzzing. no increase in buzzing with rpm. nothing.
i understand it is a grounding issue. i hope to get a more defined answer from the circumstances i have described.
I think that the reason there are no replies here is that there are several possible causes for buzzing in radios, but they all result in a buzz that is related to engine RPM. The fact that the pitch of your buzz is not RPM-related has us stumped.
I would try jumpering power to the radio fuse so it runs when the key is off and see what it sounds like. I would also try pulling the fuse to the heater fan, alarm, any amplifiers of course, and unplugging any car chargers or other rectifiers you may have plugged in.
If you find the problem, please post what it was.
Also, if you can describe the buzz more clearly, we might be able to diagnose the problem.
For example, if you mean that there is a lot of background noise, and that the signals are weak – especially if this is on AM, rather than FM – then a faulty or loose antenna (or antenna ground) connection is a good guess. Depending on where the antenna and its connecting cable are, that is something that MAYBE got knocked into when the timing belt was changed.
In general, the first things to check are the antenna connections and the power connections.
I agree that the first place to check is the battery power conn. the second place to check is the plug in from the antenna to the radio. then the ground from the radio case to the chassis. when you turn on the ignition key, even if you dont start the car, you send power to several low draw sides of relays, and if there is a drain at one of these points it might also cause this problem.