News

System Protection Fuse Holder Module (456)

Discussion in '456/550/575' started by Qavion, Dec 18, 2019.

  1. Qavion

    Qavion F1 Rookie

    Feb 20, 2015
    3,365
    Sydney
    Full Name:
    Ian Riddell
    Hi, folks
    Just wondering if there are any electrical gurus out there who understand the symbology in the WSM wiring for the "System Protection Fuse Holder Module" (found in the passenger footwell area). Namely, the box symbols and "T" shaped symbols.

    Image Unavailable, Please Login

    None of the symbols seem to represent fuses. There are numbers in the diagram (1~16), and they seem to be attached to the box symbols but there is an extra row of boxes labelled (A, B, C, & D) attached to nothing (20 boxes in total). All the T-shaped symbols are attached to the external wiring, so they may be fuse terminals, but there are boxes also attached to the external wiring (top row).

    The boxes are joined by lines, so may be part of a bus bar system. If a "box" and a "T" represent a fuse, then why is there an extra line of boxes?

    I'm currently trying to create a wiring diagram for the doors and windows. There are 8 wires going from the window/door system to the system protection fuse holder. The diagrams link all of these wires to either a box or a "T" symbol, but it doesn't tell me which fuse they are attached to.

    Thanks
    Cheers
    Ian.
     
  2. Cribbj

    Cribbj Formula 3
    Rossa Subscribed

    Jan 1, 2011
    2,070
    Houston
    Full Name:
    John
    Ian, sometimes the French wording is easier for me to understand than their English. Could you do a copy/paste of that wording and maybe I can make out what they're trying to say? I'm assuming you're working from the old manuals that are in Italian/French/Spanish/English?
     
  3. Qavion

    Qavion F1 Rookie

    Feb 20, 2015
    3,365
    Sydney
    Full Name:
    Ian Riddell
    This is in the wiring section, John. No text is provided relating to the symbols. It's simply a fuse holder. Power to the fuseholder comes from either the battery (via the maxi-fuses under the hood) or the ignition key.

    I think we're going to need a Rosetta Stone for this one ... Ferrari-esque to English :D
     
  4. Qavion

    Qavion F1 Rookie

    Feb 20, 2015
    3,365
    Sydney
    Full Name:
    Ian Riddell
  5. Cribbj

    Cribbj Formula 3
    Rossa Subscribed

    Jan 1, 2011
    2,070
    Houston
    Full Name:
    John
    Ferrari sometimes use symbology in their schematics that actually resembles the part itself. These connectors do look kinda like male/female spades.

    Perhaps the boxes are busses and the "T's" are the load side conductors leaving the busses? But why have 4 separate busses? Normally there's only two or three - one for "Always on" one for "Ignition on" and maybe another for "Accessories on".

    The ABCD boxes appear to be spares?
     
    Qavion likes this.
  6. Qavion

    Qavion F1 Rookie

    Feb 20, 2015
    3,365
    Sydney
    Full Name:
    Ian Riddell
    That was my thought, too, but there are 16 fuses, so you would expect 32 spades.

    Possibly.

    Checking the codes, the top row boxes are definitely attached to supply lines. G is ignition, R is battery.

    Image Unavailable, Please Login

    If each fuse occupies a box and a blade, this leaves the odd numbering system to sort out. The numbers and letters may simply be the plastic holder "hole" identification and not fuse numbers. You would think if the numbers corresponded to the fuses, they would have put the numbers between the box and blade symbols like this (?)

    Image Unavailable, Please Login


    Also, the numbering system may show the numbering as seen from the underside of the unit, so may not represent the fuses at all. So I'm back to not knowing if the numbers correspond to fuses (kinda important in a circuit diagram).

    Thanks for your feedback John

    Cheers.
     
  7. Qavion

    Qavion F1 Rookie

    Feb 20, 2015
    3,365
    Sydney
    Full Name:
    Ian Riddell
    Update: After shifting those numbers downwards to match up with the "T" symbols as in the second picture (in the post above), the numbers seem to correspond to fuse numbers.

    For example, pin 14 is linked to "40D" in the wiring diagrams, which is the Rear Fog Light Module. According to the WSM, fuse 14 is the fuse for the rear fog light module. Pin 14 is on our theoretical ignition bus bar, and the fog light won't run on battery power, but ignition power, so that is some evidence that the bus bar theory is correct.
    Another example: Pin 4 supplies power to the clock. Pin 4 is on the battery bus, which makes sense. You don't want the clock to stop working when you turn off the ignition. The WSM doesn't specifically mention that the clock is powered by fuse 4, but just says fuse 4 is for "instruments".

    If I can find a few more examples, I'll include that modified fusebox graphic in my wiring diagrams.

    For example, does the 456 glovebox light, the sun visor light and the trunk release button work with the ignition off? This will prove that fuse 8 is on the fuse box's battery bus.

    Thanks!

    This stuff will be quite useful as the driver's handbook sometimes doesn't tell you which fuses are responsible for some specific items on the car.
     
  8. Qavion

    Qavion F1 Rookie

    Feb 20, 2015
    3,365
    Sydney
    Full Name:
    Ian Riddell
    The evidence became more and more compelling, so I've added the updated fuseholder to all my 456 diagrams as applicable.

    Here's my latest (mostly completed) diagram:

    Windows and Doors Wiring Diagram (456)

    I'm not really familiar with the electromechanics of the door locks on the 456, so some of the labels are still a mystery. Also, there are two red wires running from the Window Control Unit (pins A12 & 13) to the Left and Right Window fuses. I don't know which wire is left and which is right.
    This diagram is to be used in conjuction with the diagram in the WSM for windows (page H32) which I notice has a few errors in it (or does the 456 have 3 window control switches?)

    Thanks to Taz for providing the diagrams for the door interior wiring and to Guido for the relay panel pinout.
     
  9. tazandjan

    tazandjan Three Time F1 World Champ
    Owner Lifetime Rossa

    Jul 19, 2008
    31,526
    Clarksville, Tennessee
    Full Name:
    Terry H Phillips
    Ian- If you do not have it, I can send you the entire expanded 456M Section L, 80 Mb, if you want it. Send me an e-mail.
     
    Qavion likes this.
  10. Qavion

    Qavion F1 Rookie

    Feb 20, 2015
    3,365
    Sydney
    Full Name:
    Ian Riddell
    Thanks, Taz... will contact you... although I'm having problem with my email at the moment. Standby )))
     
  11. theunissenguido

    theunissenguido Formula 3
    Silver Subscribed Owner

    Jan 21, 2004
    1,495
    Argent/Brasil/Blgium
    Full Name:
    Guido
    Qavion likes this.
  12. Qavion

    Qavion F1 Rookie

    Feb 20, 2015
    3,365
    Sydney
    Full Name:
    Ian Riddell
    It is, Guido, but the 456M WSM shows only one extra (50amp) fuse for the ABS/ASR system. Maybe later cars have two 30amp fuses instead of one 50 amp fuse.

    My ABS/ASR digram includes the extra 50amp fuse.

    Do you have the part number for that harness?
     
  13. Qavion

    Qavion F1 Rookie

    Feb 20, 2015
    3,365
    Sydney
    Full Name:
    Ian Riddell
    I see in the F360 diagrams, that the fuse slots are more easily identifiable.

    Here's an F360 fusebox with 6 fuses and 4 relays.

    Image Unavailable, Please Login
    There is a bus bar (or line) shown attached to one of the LR wires.
     
  14. fished43

    fished43 Rookie

    Aug 15, 2012
    16
    Full Name:
    Dave


    I can't seem to find these additional fuses claimed to exist in the "passenger footwell area". Have searched all over my 1995 456GT and no joy. Can anyone please provide additional clues? Thank you.
     
  15. Qavion

    Qavion F1 Rookie

    Feb 20, 2015
    3,365
    Sydney
    Full Name:
    Ian Riddell
    Apparently that additional fuse holder is not found on the 456, only the 456M. I did see some additional fuses in the engine bay in YouTube Ratarossa Ferrari 456 video on parasitic current draw. I don't know if that will help, Dave.
     
  16. fished43

    fished43 Rookie

    Aug 15, 2012
    16
    Full Name:
    Dave
    Ian, Thanks. You would think there would be fuses somewhere for the electronics not provisioned in the standard fuse panel (seat controls, windows, door locks, hazard, other instrumentation). Perhaps they are just scattered around on older 456s (under carpets, etc) vs neatly organized in a SPF Module (456M)? I will double check the engine bay again per your suggestion.
     

Share This Page