348 Mouse track shoulder harness

My pleasure. I get a little bored in my retirement. I sometimes feel like a detective when I'm working on this stuff.... All the clues are starting to make sense.

Do you already have direct access to the 2 pin motor plug? I was worried that we would get stuck trying to figure out the wiring on the 9 pin plug under the seat. The diagram Wade provided appears to be for the GTS (and GTB). It shows only 6 wires going to that plug. I suspect the motor wires are the pink and the (large) blue wires going to that plug are the passenger side motor control wires from the ECU because they are heavy duty. The colours should change at the 9 pin plug to a black and a red wire (to be confirmed). The red and black wires suggest that the motor turns in only one direction, but I can't see the mouse going in both directions if the motor only turns in one direction (unless there is some kind of mechanical wizardry involved).

Here's my latest effort. The zig-zag lines in magenta are pure speculation:

GTB/GTS Mousetrack Wiring Diagram

 

Mine had a similar behavior. I ended up changing our the entire passenger side mouse track and motor. The switches were good, but the mouse wouldn't activate on it's own. There is no sensor/switch in the seat. The ECU located beneath the dash console ended up being fried. FYI, there are at least 3 versions of passenger restraint ECU's. My '93 had V1. I replaced it with a more robust V3 and everything works fine. The version number is stamped on the outside of the box. You can get a used ECU from GT Parts. I think they are $125 or so. If you ever disassemble one and look at the innards, it is pretty obvious where the weakness are in the earlier boards, in comparison to the V3 board.

 

I'm curious to know what's inside that "home base" on the track. I'm wondering if the system needs two microswitches. One for the seatbelt light and one for motor control. There are four wires going in there (not including the blue and black wires going to the other end of the track).

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Green and black may be for a microswitch for the indication circuit (in series with the microswitch under the backup receptacle).
Orange and brown(or another black?) for a limit microswitch which stops the motor when the mouse arrives.

I'm not sure that one faulty microswitch would cause your problems though. One switch might stop the belt running in one direction, but you are having problems with both directions.

It looks like you will need a torx bit to get inside that unit.

 

If it's not too difficult and you have time. If the passenger's seatbelt light is illuminated for any reason, could you try disconnecting this small white plug (ignore white arrows).

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The driver's side plug is shown in the photograph. These plugs are located on the door side of the seat.

I'm trying to determine if this is for inhibiting belt operation, for inhibiting the light, or both.

Hope the original poster of this photograph doesn't mind me recycling it )))

 

I mentioned early in the post, that connection if unhooked will cause the belt lights to light up thinking belt in not connected and it will prevent the belts from working at least on my car. When I pulled the seats out the belt lights were on and belts did not run. So if that connection is loose which can happen if seat is slid all the way back, it can strain the connection and cause intermittent operation and belt light on. When I redo my carpet I will lengthen those wires a few inches and redo the connector, the wires slip right out of the plug on mine. I never heard if the OP checked that connection, the issue may just be that.

 

Ugh... This may be more complicated than I thought. On a non-mouse seat belt type system, plugging in a belt will change the position of the seat belt buckle microswitch to "open" (no current path, no light). I assumed the indication circuit would be similar on the mouse type.

Eric, did you just disconnect that small 2 pin plug or the larger 9 pin plug under the seat? The computer may illuminate the light with the entire seat removed because the whole system has been disturbed.

Normally, on that type of microswitch, if the wires are attached to the two outer contacts (and not the middle one, the switch will show closed circuit when the microswitch arm is not pushed down. When the buckle is attached to the male section, the microswitch opens.

 

If the mouse belt won't run home (to its aft position) and you use the backup receptable, will this extinguish the seat belt light (or will that remain illuminated to remind you the auto system is broken)?

 

Thanks, Robin. This will make the system a lot easier to understand.

Things to look for:

Wiring colours on either side of the 9 pin plug. I can't identify the four wire colours going into the mousetrack. In some photos I see green, black, orange (or yellow or a combination of yellow and orange), and perhaps brown.
Why are there four wires going into the mousetrack "home position". Are there two microswitches there? Is one for mouse control and one for the seatbelt light?
Is there a splice joining up 3 or 4 black earth wires (hidden by the black plastic sheath around the thicker part of the harness under the seat).
Does the backup receptacle for the seatbelt have a "normally closed" microswitch (and what are the two green(?) wires on the microswitch plug attached to).
Is the microswitch at the foward end of the track normally closed?

Is this the same for the driver's light, too (i.e. if the driver's door is open and you use the backup receptacle, does that not extinguish the light?). Seems like a bad design. You would have to drive with the seatbelt light on all the time. It seems like the backup receptacle microswitch is only there to disable the mousetrack system. However, as a result of disabling the mousetrack system, the ECU must put on the seat belt light.

 

Whats the part number for that door open switch are you referring to 134423?
https://www.ricambiamerica.com/car-diagrams/ferrari/v6-v8/348-group/348/doors-inner-trims-not-for-spider/134423-switch.html

 

Probably too late to help, but....

https://www.ferrarichat.com/forum/threads/door-switches-160-161.561839/#post-145639585

Sounded like a simple fix until it crumbled in your hand

 

Is the rectangular hole above the regular door light switch, the location of the switch for the seatbelt mousetrack system?

https://www.ferrarichat.com/forum/posts/145616977/

 

Disregard. The other message thread answers my question

 

Ah.. I forgot the mousetrack would stop you getting in that area. If you have the time and while you're in that door pillar area, would you be able to make a resistance check on the "A station" wiring plug (if it's easy to get to). I want to see if it's closed circuit or open circuit with the mouse in the aft position or, if easier, see if it's open/closed circuit with the mouse in the forward position. Thanks.

Latest diagram... Refresh browser if necessary to see amendments

 

Loads of great info in this thread! Thanks for sharing with the rest of the 348 Brotherhood!

 

Thanks for the update, Robin. It's kind of disappointing that the door switch didn't fix the problem.

I was hoping for a cheap fix, such as a microswitch replacement (at one of the ends of the tracks). The light may be a clue that a switch input is missing. I can't imagine the motor would wear out. It's only used for a few seconds each drive. The cable which pushes/pulls the mouse might be a problem though if it's not kept properly maintained. I also wonder if the gearbox cogs are made of crumbly plastic like headlight lifters and HVAC actuators? Does it look like the motor gearbox is easy to get into?