strange noise when I turn on ignition

[jleitzs]

I have a buzzing popping noise when I turn on the ignition. Sounds like it is coming behind the radio. You can hear it while the truck is running as well. Its not the ac fan or radio. Dies anyone know what this might be? It seems to be non mechanical.

[sredmyer]

Originally Posted by jleitzs

I have a buzzing popping noise when I turn on the ignition. Sounds like it is coming behind the radio. You can hear it while the truck is running as well. Its not the ac fan or radio. Dies anyone know what this might be? It seems to be non mechanical.

What year truck and what type of radio is it (nav or 6 disc changer)? How loud is the noise? Is it soft enough that if you weren't specifically listening for it you might miss it or is it fairly loud?

Steve