With all the electrical problems you're having it sounds like one of the computer modules had a stroke or something is wrong with the wiring. There's a diagnostic mode available through the MFT that might help.
(shamelessly copied from the Internet)
- Make sure there is no CD in the system
- Set MFT to AM/FM
- Press and hold the eject button and...
- Immediately after press and hold the right arrow on the center wheel while still holding the eject button
- Hold both buttons pressed for about 12 seconds
- Screen goes black and MFT enters diagnostics mode