456gt wont start

i dont own a 456, but i would next check your relays and see if there is another one the same as the fuel pump relay. switch the relays out and see if the fuel pumps work, and if the other component has now failed. if you cant get it to a shop, get a multimeter and check the big, obvious pathways. if you have other stuff out in the dash i would suspect an ignition switch or ignition relay failure also. again i am just a dumb carb 308 guy ...... best wishes.

 

I was cleaning my fuse contatcts today, noticed the radio and a/c are on the same fuse circuit. Are you really sure the fuse is OK? Try swopping in another one.
Also clean up the fuse contacts, they get tarnished.
Regards,
Ron

 

I am also wondering if the battery is low on voltage - the main engine ECU(s) sense low battery voltage and presumably nothing works then.
Regards,
Ron

 

Now I see you replaced the battery too, that leaves the pump relays as said before or the ECU itself. Try cleaning the contacts on the pump relays and test out the relay by applying 12V to low current side (smaller terminals) and listen for click of relay.
Regards,
Ron

 

You say it doesn't turn over? By this, do you mean that the starter doesn't even spin when you turn the key? If so, I suspect a fault at the ignition switch itself, because though I've never examined a 456 or any modern Ferrari for that matter, I've never seen a car that had the ignition switch to starter protected by a fuse. The other non-functioning items may be fuse protected though so checking all the fuses is a good idea regardless.

 

It sounds like the factory alarm system may be malfuctioning. Is the alarm system LED on the dash illuminated? Do you get any response from the alarm system when you try to disarm it?

Brian