Made some minor repairs - buzzer - door handle - turn signal

He’s talking about unplugging the speaker. Isn’t there a fuse for that? Pull it out. Disconnect the power to the speaker setup.

 

Torrance, the original poster was talking about opening up the speaker unit and desoldering the leads on the speaker. Another poster, however, just unplugged the unit. Same thing? No. The speaker unit on the USA/CAN/JAP F355 has an 8 pin plug, so it definitely has more functions than a speaker. For some reason, the speaker unit has a relay inside it attached to the brake warning system. On non-USA/CAN/JAP cars, they don't have a speaker unit, just a smaller relay unit by itself (attached to the brake warning system). I'm struggling to understand why that relay is in that particular unit and what it's used for (the speaker circuits appear to be isolated from the brake circuits inside the unit).

At first I thought you wouldn't get a brake warning light at all if you unplugged the speaker unit, but the power for the relay comes from the "START" contact of the ignition lock. So I assume the brake warning light illuminates as self test during engine start. I just don't understand why they chose to make it illuminate at start and not just with the key in accessory. The ABS warning light does a similar thing, but this is mentioned in the manual.. and specifies that the light remains illuminated approximately 3 seconds after start.

I don't have a diagram showing where the speaker (alone) gets its power from. The wiring diagrams are Euro-centric. Looking the diagrams in the WSM, it appears that power comes in on pin 4, but I recall that someone said this was the pin for the seat belt circuit (on USA cars).

Do the USA car handbooks mention a fuse? It certainly would be easier pulling a fuse than removing the unit, opening it up and desoldering wires.

 

Patching together various wiring diagrams, I have:

Module pins on USA cars:
Pin 1: Signal from RH door (also goes to Window Control Unit) (White/black wire)
Pin 2: Signal from LH door (brown/white wire)
Pin 3: unused? (if used, possibly power for the speaker) (wire colour unknown)
Pin 4: Signal from seat belt (pink/yellow wire)
Pin 5: To brake pad wear switches, brake warning [!] light and brake fluid level sensor (pink wire)
Pin 6: To earth (black wire)
Pin 7: unused? (if used, possibly power for the speaker) (wire colour unknown)
Pin 8: Power from ignition lock during start (white wire)

That photo seems to show only 7 used pins. The wiring diagrams show a "pin 8"

Unfortunately, I don't have a USA car to confirm this.

 

G’day mate! Aircraft engineer, mechanical or electrical? You seem on top of it.

I’m too lazy to go to my car and verify the things you listed. So are saying the little box the speaker mates to behave like an “ECU”? It verifies all conditions is normal and if not the speaker sounds? If so I can put them into a Line Logic format for easy troubleshooting. I don’t do manufactures drawings.lines crisscross all over the place with no labels.

 

G'day, Torrance.... Former/retired aircraft (avionics) maintenance engineer here... but never on top of these Ferrari diagrams (Italian/Ferrari is quite different from USA/Boeing). They take a few dozen attempts to get right. The problem is that there are too many variations from one car to another and from one country to another... and there is only one set of wiring diagrams available to the masses (Euro 2.7 car diagrams).... although we have managed to find some 5.2 ECU diagrams. Also, when I do wiring checks on my 5.2 (mostly Euro) Australian spider, I can see how the car has been modified from the 2.7. Note that Ferrari tried to do as few changes as possible to the wiring (so they didn't have to rewire the whole car).

I think calling the buzzer box an "ECU" would be flattering it too much. It's more like a junction box (for all the systems which require a buzzer) and a simple relay circuit to put on the brake warning light [(!)] at a specific time.

Now, on my car... which doesn't have a buzzer for seatbelts unfastened and doors open and doesn't have an independent [PARK] light for the handbrake, but does have a [(!)] light (for both handbrake and brake warning)... and does have a smaller non-buzzing module for handling the illumination of the [(!)] during "preflight" checks.... I confirmed the following:

When you put the ignition key to the II position (second position from OFF), the [(!)] light does not illuminate if the handbrake is OFF. It will illuminate if the handbrake is on.
If the handbrake is off and you crank the engine, it illuminates when the engine is cranking as a "preflight" light test. As far as I know, this is how the USA cars operate, too. The USA cars, however, have an independent handbrake [PARK] light and I have to go by what the USA folks have said (with 100% confidence) on how that behaves. Unfortunately, I don't have a circuit diagram for that, so I won't be much help in diagnosing faults with this type of light.

Anyway, if you do disconnect the buzzer unit completely, you will lose the buzzer, but you will also lose the "preflight" function for the [(!)] brake warning light. The brake warning light will, however, illuminate if you have brake fault (assuming the lamp hasn't blown). The brake fault sensors talk directly to the warning light.

Clear as mud...

 

Just a slight modification to the above message... I showed the independent park brake light as [PARK]. Looking at the manual, it's [(P)]

Do all the USA cars have an independent park brake light or is it only the early cars?

 

I asked because you seem to grasp these cars electrical inner working. That ability will come handy. Time doesn’t sit still. Parts for these cars will dwindle. At some point, reverse engineering the parts or replace them altogether with something equal or better is a must and you can’t go about it without understanding the details. I imagine every issue, operations have been addressed. From the electrical side, It would be beneficial to explain it in a logic format(PLC/Ladder Logic) for easy troubleshooting. I’m too lazy to verify every device functions. Just need to know what something does or want to do in what order, I’ll come up with a control circuit.

One item I find baffling, why did Ferrari use hydraulic to open/close the spider top. Unless I’m missing something, an electric motor would have been a better method. Just thinking out loud. And by the way Torrance is not my name. It’s a city where You will find cool people with jell in their hair

 

Ooops... I must be crosseyed. "Roth" is ok?

Unfortunately, I don't know much about the inner workings of the more complex devices (which would be part of flow chart logic), just how they are hooked up.

Not sure about hydraulics vs electrics either. Perhaps the roof requires activation forces and speed beyond the range of electric motors (of a comparible size). In the case of aircraft, e.g. flap systems.. they use hydraulics or pneumatics, but also have painfully slow electric motor backups (but care must be taken with the electric motors so as not to overheat them, especially on the ground where there is no cooling airflow). Hydraulics is definitely not for noise limiting on the F355. The quietness of hydraulic actuators is offset by the noise of the pump.

Anyway, my own car is calling me... multiple electrical and mechanical issues... plus a few random wiring checks to quench my own curiosity