Where is the fuse for a 99 expedition pre amp?

In a 1999 Ford Expedition, the fuse for the audio system, including the preamp, is typically located in the fuse box. The main fuse box can be found under the dashboard on the driver's side or in the engine compartment. Look for a diagram on the fuse box cover to identify the specific fuse related to the audio system or preamp. If the audio system is not functioning, check this fuse first and replace it if necessary.