Clicking noise
 

I have a clarion deck and yesterday randomly there was a clicking noise that started. It happens once the radio is on, if I'm listening to the radio or i pod it doesn't seem to matter. It happens like every three seconds and stays at a constant level that doesn't change with the volume level. Any ideas of what could be causing it would be great. Thanks for the help

is it in the deck or the speakers that you are hearing that sound?

in all the speakers, tower and inside the boat.

does it do it if you mute your sound?