Calling all F355 radio gurus..... See https://www.ferrarichat.com/forum/posts/149994962/ The wiring on my Sony unit doesn't match the Sony workshop manual I have. I can't see how the radio turns on/off, as the only power going to the radio seems to be live battery power from frunk fuse 4. Live battery power feeds into a mystery black box under the dash next to the radio. There is a fuse mounted on the box, but it's obviously not just a fuseholder. Image Unavailable, Please Login It's not a relay as there are no other wires going into the box. Is it some kind of power filter? Image in the Sony manual: Image Unavailable, Please Login Does the Sony (as fitted to the F355) only come on with the button on the front of the unit? Thanks in advance.
It's just an inductor to filter noise. Simple low pass filter. Image Unavailable, Please Login You have power backwards. Wiring: Red = switched power. Yellow = Battery. Image Unavailable, Please Login
Thanks, John... I just managed to pull it apart myself to see what was in it. Just a big coil... in series (?) with the power wiring. Image Unavailable, Please Login Not sure why it's only for one of the power inputs into the radio.
Given that certain things require power at all times (memory...) and others only when the unit if on my guess is the yellow is the main power source and red powers a relay that directs power to the amplifiers, tuner and tape deck parts, controlled by the on/off button. But I'm just guessing. You can down load the service manual here: https://archive.org/details/manual_XRF21RDS_SM_SONY_EN/page/15/mode/2up Choose the one that is listed as "PDF".
