E1 is the Radio fuse (7.5A). D9 is the Amplifier fuse (15A), D8 is option code 680 upgraded Digital Sound Pkg. Radio and Sound system (7.5A) - if your car has this.
Also, disconnect the battery and reconnect.
Finally, pull the faceplate of the radio and clean the contacts on the radio and faceplate with a q-tip and alcohol - that's what it most likely is. The Faceplate communicates all the control functions (buttons) to the Head Unit electronically through the contacts on each. These get dirty, corrode, etc. Most of the issues with these radios are caused by these contacts being corroded, dirty, or out of alignment.
If you don't know how to pull the Faceplate, go here:
http://www.beckerautosound.com/pdf_guides/om43-4462.pdf
Threaded Mode
