348 Mouse track shoulder harness

I did a quick scan of the wiring diagram for the Passive Safety Belts, had to piece together four scans. You can zoom in closer with the attached pdf.

Also attached is a photo of the List of Components. I couldn't scan the list effectively.

Hopefully this will help.
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Here's a consolidation of Wade's diagrams (with colours and labels where known).

F348_Passive_Type_Seat_Belt_Wiring_Diagram

However, there are quite a few loose ends. Wires which go nowhere, including the one which supplies power to the two seat belt control units (which then supply power to the seat belt motors). Also, the seat belts don't seem to be shown. It's the same for the F355. You have to go searching for the wires. Some have had to invest in electronic wire trackers to figure out where the wires go.

 

Very nice!

Yes, it seems to be an afterthought type system for sure. When I was going through my previous 348 I'd often ask myself "now why did they do this?"

 

For example, why is this system tied to the speedometer? I had a burned speedometer and traced the problem to stray voltage from one of the seat belt ECUs (apparently shorted internally). Also, the wiring in the car didn't always match the wiring diagram.

https://www.ferrarichat.com/forum/threads/348-speedo-burned-internals.503511/page-7#post-144326815

https://www.ferrarichat.com/forum/threads/348-speedo-burned-internals.503511/page-7#post-144334981 (this post and the next).

 

Thanks, Wade. I've incorporated all those changes into my diagram.

Version 2:

F348_Passive_Type_Seat_Belt_Wiring_Diagram

 

Does anyone know what these are on the wiring diagram:

"Inserted key alarm control switch"
"Pushbutton for passive type seat belts (passenger side)"

Are these simply the switches in the seat buckles? I've only driven a car once with this type of seat belt system (back in the '80's). Are there any pushbuttons for seat belt control?

 

For the dash light, check the white plug under the outer rear bottom of the seat. If it is not connecting the dash light will not go out. The wires can come loose but looks connected.

My car had intermittent belt operation too previous owner replaced the belt ecu works great now.

Hope it helps.

Sent from my LM-Q710(FGN) using FerrariChat.com mobile app

 

That was my guess, the switches in the seat belt latch receptacles; driver and passenger - Items 217 (mislabeled in the wiring diagram?) and 218.

 

LOL! I am sorry I can't help but laugh. The agony and the ecstasy of an Italian car!

 

Does the seat belt warning light come one whenever any/both belts are unfastened and the ignition is turned on? Does the light only come on if the driver's seat belt is unfastened? I don't think there are pressure sensors in the seats, so only the driver's seat seems important.

Does the alarm only sound if any seatbelt is unfastened and the car is above a certain speed? Does the alarm only sound if the driver's seat belt is unfastened?

 

Intriguing questions, and hopefully someone here can verify...

My current 348 is Canadian Spec., which has normal seat belts (i.e. three-point).

 

There seems to be a lot of wires missing, too. I've been trying to compare online photos of the track assembly with the diagrams. Instead of a 7 pin plug feeding the track and motor assembly, there is a white 9 pin plug . Only 6 of the slots in this plug appear to have pins, but there seems to be about 8 or 9 wires on the assembly itself (perhaps the earth wires are spliced). These wires run to...
A two pin plug for the motor (with red and black wires).
Four or 5 wires going to the driver's side seat belt buckle area. A black and a blue wire (or a black and grey wire) appears to run along the entire length of the track, perhaps to a switch at the forward end of the track.
A two pin plug which doesn't seem to be long enough to go anywhere.

I tried to add some of these wires to my diagram, I started my modifications on the passenger's sidebut there is too much information missing:

Passive Type Seat Belt Wiring Diagram Version 4

Microswitches are shown in the Ricambi America parts diagram where the male portion of the lap belt emerges. Are these related to the lap belt or the mousetrack belt? (Item 48)

https://www.ricambiamerica.com/car-diagrams/ferrari/v6-v8/348-group/348/seats-and-safety-belts-valid-for-usa.html

Perhaps an ECU is overkill at this point?

 

Just picked up a few more errors in the Wade's Ferrari diagram relating to ignition power.

Fuse 1 is connected directly to the battery (ok), but there is a line in the original diagram going to the blue wire on the ignition from the battery terminal on the passenger footwell fuse panel. If this were the case, you wouldn't need a key to start the car.
Also, the 2.5 L (blue) wire running from splice 243 to plug E on the relay panel is hooked up to the wrong pin. That would illuminate the ignition lock light permanently (whenever the ignition key was in RUN).

I've just corrected it in my diagram (Version 6).

Seat Belt Wiring Diagram Version 6

 

I just realised that earlier cars have different wiring (so more complications). The early cars (at least passenger seats) have an additional long harness going behind the occupant's head, from the motor to the seat belt reel.

e.g. P/N 62894900

https://www.ricambiamerica.com/car-diagrams/ferrari/v6-v8/348-group/348-1989-1992/seats-and-safety-belts-valid-for-cars-with-passive-safety-belts-valid-from-car-ass-nr-5299.html

Newer passenger motor harness shown here:

P/N 65377200

http://exoticsalvage.com/94-ferrari-348-seat-belt-rail-track-motor-right-63637600-65377200-db800805

 

Robin, if you can access those 9 pin white plugs under the seats, would you be able to give me the wire colours on both sides of the plug on the passenger seat side?

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I've used arbitrary numbers. I don't know if they are marked. Note that Ferrari uses two shades of blue. The "car side" will have some wires with two colours. On the track side, there will probably only be single coloured wires.

Until we know what wire goes where, it's going to be hard to make a diagnosis. Probably your best bet is to simulate both doors closed (by jamming both "door open" switches in the closed position) and buckling both seats, then shutting off the battery and comparing the driver's side wiring with the passenger's side wiring on those 9-pin white plugs. If there are more wires on the passenger side Vs the driver's side, then that makes things a little more difficult.

At this point, we don't know if the light is illuminated by combinations of belt switches on a particular seat. How does the system know someone is sitting in a seat?
The logic might be:
If the lap belt is connected, then check the position of the "mouse". If it's not aft, turn on the seat belt light.

If there's a microswitch at the "mouse aft" position, then that might be the most likely thing to illuminate the light.

 

P.S. Ignore that orange colour on pin 2.

My latest ramblings/discoveries on the passive "mousetrack" seat belt system

Updated diagram (version 11)

Not related to Robin's problem, but I discovered an input from the reverse gear selection switch. This may or may not inhibit buzzers and lights when you are reversing.

I didn't realise that the switches for "doors open" (217 and 218) were dedicated switches and not the switches used to turn on the interior lights.

Not shown in the parts diagram is the variation between the early (348 TB/TS) harnesses and the later (348GTB/GTS) harnesses. Looking at online photographs of early harnesses for sale, both the driver's and passenger's harnesses have an additional harness going from the white 9 pin plug under the seat to the belt motor (and then to the seatbelt reel). I read on FChat that the seatbelt reel has some kind of locking solenoid which locks under certain conditions (like people tampering with the wiring). This may not be used on later cars as the wiring harnesses are simpler. Note that if you use Google to search for a particular assembly's part number, it may take you to photos of assemblies with different part numbers (Hence my earlier confusion).

Still unknown:
1) The function of the microswitches which are activated when the backup male receptacles for the mousetrack seatbelts are used. If the mousetrack system is inoperative, a mouse seatbelt can be plugged into a receptacle on the door side of the seat.
2) What the wiring diagram items "228" and "229" refer to. "Belt retractor for driver's/passenger's seat". If these are the locking solenoids on the mousebelt reels, then why are there 3 wires? Also, why is this shown as a separate harness in the original diagram, but the wiring in early system photographs goes through the 9 pin plug under the seat.
3) The pinout of the 9 pin plug.
The 9 pin plug feeds up to 5 subsystems:
a) Motor (2 wires)
b) The aft mousetrack assembly (4 wires)
c) The backup receptacle microswitches (2 wires)
d) The solenoid lockouts on the reels (3 wires?)
e) The limit(?) switches on the end of the mousetracks under the dashboard (2 wires). Colour variations noted here.

Most of the posts on FChat seem to be dedicated to deleting/inhibiting the mousetrack system, so there is limited information available. For posterity (and the die-hards), I'd like to at least figure out how it is supposed to work

 

Ah.. good... I've started drawing diagrams specifically for the different types. Does the spider only have one seat belt light or one for each seat? This will make faultfinding half as easy if we can isolate the problem to one side.

Although the ECU does put on the light, the ECU is basically looking at the position of microswitches on various components. The light needs an earth from microswitches to illuminate. This earth is removed if the belts are in the right positions.

E.g. If you use the back up seatbelt receptacles, does the seat belt light extinguish?

Is it one side or both sides you're having problems with?

 

Will the light extinguish with the mouse seat belt in the back up position (if I am describing this correctly). i.e. when the mouse track system fails, you have the option of putting the mouse belt (female) end into a fixed position on the door side of the seat.

The relay/s will be inside the respective ECU. If you can hear a relay operating, this is telling you the door switch is ok and that the ECU is trying to operate the motor. We have to figure out why the motor isn't working.

1) The mouse position sensors may be falsely telling the ECU that the mouse has already travelled to the right position (i.e. there is a broken microswitch in the seat track (aft position).
2) The motor may be tired.
3) The relays may be energising, but the power contacts may be faulty (There is probably one or more small mechanical relays inside each ECU). These might be far cheaper than an ECU, but if you're not handy with a soldering iron then having someone replace it might be just as expensive as buying a cheap ECU. I don't know about the F348 Spider, but the F355 has lots of these little relays. They are still relatively easy to obtain.
4) There may be something mechanically wrong with the mousetrack... like something jammed in the track.

Is it possible to determine if the belt is more reluctant to travel in one direction rather than the other?

 

P.S. Will the driver's side seat belt light go out without connecting the lap belt (I can't find any microswitches in the parts manual relating to the lap belt). I thought the vehicle safety laws wouldn't allow the lap belt to have no input into the seat belt light system, but I may be wrong.