A quick, cheap and permanent fix for broken 355 seat potentiometers

Very very trick, great work and thanks for sharing the info.

 

Would this mean that one could wire in resistors = to these values and that would trick the control unit into thinking the seat was in the fully forward position therefore removing the need for the seat potentiometer?

 

are you saying that the gears are so destroyed that the black ball is no longer rotating and that the 3 resistance values are now fixed at 500 ohms, 4.4Kohms, and 4.6Kohms, and they would remain that way whatever the position of the seat is?

Second question is... how do you tell which seat has the bad potentiometer?

 

At the moment I have removed the potentiometer from the rail and plugged it back into the wiring but left it so it hangs out from the bellow the front of the seat, i then set it to the required impedance for the seat forward position using a small screw driver and now my roof works fine, i just have to flip the seat back forward to clear the roof as it moves.

This of course was a temporary fix, i have just obtained a new pot and will fit it this weekend if i get time.

 

I got it now. As for me, I would just leave it off forever. How do you figure which seat was bad?

 

That was the easy bit, I became good mates with my local ferrari technician 12years ago !!!
Drove in, stuck it on the SD2 and checked, unfortunately i think that is the only way to check

 

My reverse engineering hat tells me if I adjust the seat all the way up, and pull the connector to measure the resistance between the color wires, and if they are not close to the 500, 4200, 4500 ohms numbers above, then that one is bad ...

Would that do it, you think? Afterall, the SD computer would just measure the resistance values via an ADC and come to the same conclusion, no ?

 

That would do the trick, the benefit of the SD2 is that you can actually move the seats from the computer screen and watch the values change, or not change in the case of my passenger seat.

Good luck in getting it sorted

 

Just wanted to thank AfastA1 for this post! Just did the same procedure and it cost me ZERO! (well, I already had a $2 tube of super glue that worked perfect).

Only thing I saw that you need to pay attention to is to make sure the black gear is put on perfectly straight so when it dries there is no unneeded stress on the gears that mesh with it.

and as some of you may have found out, the Potentiometer can only turn so far, so using your meter, set it for the full aft position then put the Potentiometer back in the car when the seat is also in the full aft position. This way there is no chance or pushing the pot past its limits.

Thanks again

John

 

small update

The 96 spider I have, the color of the wires were:

Red, Yellow, Black. I figure out that these are equivalent to: Pink, Yellow, Brown.

 

I fixed my seats !!!! Removed both seats, removed the potentiometers, turned them until the values are 600 ohms, zip tied them to the motor without putting them back on the shafts, put the seats back, and ... the top works ...

Zero dollars! Permanent fix!

 

So does this mean your pots are fixed permanently at 600ohms? Or do they still work and the seats move automatically when you put the top down?

 

I removed the pots and fixed them at 600 ohms. The pots are zip tied to the motors so that they are no longer turned by the motor actions. Therefore, when the top ECU checks, it thinks that the seats are already at the front most location and activates the top pumps. It is now up to me to make sure that the seats are at a non-interfering location.

I hate computers that think they are smarter than the people who designed them.

 

I have a couple good pots available from a '97 355 spider that I dont need, if anyone here wants or needs them, i'll sell em cheap!! PM me and make an offer!

 

This is great work guys. I love this site. I've never had this problem, but I might at some point.

Taking away another crazy priced fix on the 355 will eventually get people to quit complaining about how they had a friends cousins buddy who once had a 355 and it cost him a bundle to keep running....

 

Jeff,

Are your pots fixed at 600ohms or do they still work? My problem is that manually moving the seats to put the top up and down is a bit of a PITA. I'd rather they moved automatically.

 

I find that the seats only have to be a few inches from the rear most position in order to not interfere. I am short legged so that is where the seats are anyway.I actually prefer that the seats do not get moved during the top operation because it means my passenger and I don't have to sit with our faces in the dashboard when the top is moving.

I actually prefer a manual top ... but that is a different story.

 

Right on. I'll have to do this.

 

LOL, like a trash compactor isn't it...

 

Digging up an old post...

I'm looking to do this now, finally. Seems some discrepancy on whether to do this full forward or full back with pot minimum or maximum. Either way work?