System Protection Fuse Holder Module (456)

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.

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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.

 

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

 

By the way, on a left hand drive 456, are the fuses numbered right to left (with the wiring harness on the 4,8,12,16 side)?

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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.

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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 (?)

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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.

 

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.

 

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.

 

Thanks, Taz... will contact you... although I'm having problem with my email at the moment. Standby )))

 

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?

 

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.

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There is a bus bar (or line) shown attached to one of the LR wires.

 

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.