F355 Spider - Seat Problem! | FerrariChat

F355 Spider - Seat Problem!

Discussion in 'Technical Q&A' started by Dem, Jun 12, 2004.

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  1. Dem

    Dem Formula 3

    Mar 21, 2004
    1,027
    London
    Full Name:
    Dem
    Hi!

    I'm new to the forum, and new to Ferrari ownership - hope I've done the right thing.........!!! ;-)

    I bought the 1997 LHD car a month ago and already I've got a problem which isn't covered by the limited warranty. Basically, when I finished a weekend drive and tried to put the roof back up, the driver seat failed to move forward. Using the seat button, it would only move back. I manually flipped the seatback forward to allow the roof to be closed and found that the seat would now move backwards and forwards again, but only about an inch! Today, it won't move at all.....

    I've heard that it is likely to be the seat potentiometer which has gone. As a temporary fix to allow me to at least move the seat back and forwards (so my girlfriend can reach the pedals when she drives!), the dealership suggested unplugging the potentiometer from the loom.

    Does anyone know if this works? I had a quick look under the seat and found two connectors off the loom, one white and one black - any ideas which is to the potentiometer and which is to the motor?

    Thanks for any help you can give!

    Cheers,

    Dem.
     
  2. PaulK

    PaulK F1 Rookie
    Silver Subscribed

    Apr 24, 2004
    4,603
    Michigan
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    Paul
    Good question.
    Im sorry but the only answear I can give you is to unplug one and see if it works. If it dosnt, plug it back in and un plug the other. If that dosnt work, then somthing else is the matter.
     
  3. Dem

    Dem Formula 3

    Mar 21, 2004
    1,027
    London
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    Dem
    Hi Paul,

    Thanks for the reply - I guess you are right in that I'm just gonna have to pull them both and see what happens. Never had any problems like this on my 300ZX...................... ;-)
     
  4. Dem

    Dem Formula 3

    Mar 21, 2004
    1,027
    London
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    Dem
    Just in case anyone was still puzzling about whether this idea works............................the asnwer is "no"!

    I pulled both plugs individually and still the seat wouldn't budge either way on the seat switch. Luckily, I can still reach the pedals, but the bird is either going to have to keep her heels on for driving, or find a cushion......!

    Oh well, it was worth a go!
     
  5. Cavallino Motors

    Cavallino Motors F1 World Champ
    Lifetime Rossa

    May 31, 2001
    14,143
    Florida or Argentina
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    Martin W.
    but the 300ZX never looked as good either :)
     
  6. wax

    wax Five Time F1 World Champ
    Lifetime Rossa

    Jul 20, 2003
    51,458
    SFPD
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    Dirty Harry
    http://www.focfloridaregion.com/techtips.htm
    I don't think it's wise to reprint the entire Q & A as focf might get fiesty, so...
    Scroll to the 5th question, which begins:
    Q. I have a 1998 355 spider the top will not open so I went to the special switch and was able to open it...
    _
    You'll see mention of a similar problem - but no greater a solution other than shop test/repair because of SD1 computer misjudging seat position.
    _
    However, now that your question has been bumped to the top of Tech - perhaps you'll get an answer from those who missed it the first time, but know a halibut more than I.
     
  7. Cavallino Motors

    Cavallino Motors F1 World Champ
    Lifetime Rossa

    May 31, 2001
    14,143
    Florida or Argentina
    Full Name:
    Martin W.
    It is always amazing to see what 355s have in terms of problems over the 348s and yet people insist the 348s are dogs.

    Never had a cracked header on a 348,
    never had problems with the seat prosition system on a 348 Spider,
    never had valve guide problems on a 348.

    All 3 are very expensive propositions to repair yet nobody really complains about them but when the $ 1300 ECU of the 348 goes bad...well its a 348 it has "electrical problems since day 1".


    The answer to your problem is:
    the car needs to go in for repair. If you want to tinker check if there is an obstruction in the seat rail. A little Shilling may have crept into the rail. Check the fuse first to make sure that the obstruction has not caused it to burn out. Then check power supply at the motor. May be necessary to take the seat out of the car. Does the passenger one work? I am not sure if they sit on the same fuse. Check that.
    The seat rails have to be nicely greased and free of dust. The little motor that operates them is not strong enough to go through grime.

    The entire power top mechanism is a joke on the 355. The 348 closes in half the time if you get cought in the rain.

    Have fun :)
     
  8. sparta49

    sparta49 F1 Veteran
    Owner

    Mar 3, 2001
    7,802
    LA
    Full Name:
    Frank
    this isn't a 300ZX :)
     
  9. goyal99

    goyal99 Karting

    Mar 5, 2002
    185
    Upstate NY - USA
    Full Name:
    V K
    If it was me, I would....

    a) if all the electrical checks out okay, then unbolt the seat and take a look at the motor....most likely the motor is gone bad...But just for grins, give it a good wack with a hammer (it worked on the seat motor of my Porsche 928 and the 928 uses 2 motors per seat!!)....Doesn't the F355 have a manual over-ride for the power seat, like a manual lever under the seat to move it forward/back in case of failure??? Sorry I don't have power seats in my 348 so I don't know...

    b) if the motor turns out to be totally dead, I would remove the pass. seat and swap the motors....A temporary fix - who cares about the passenger's comfort, right??

    c) take the bad motor to someone who can fix it for cheap (i.e. avoid a trip to the dealer).

    Cheers - VK
     
  10. cgperry

    cgperry Formula Junior
    Rossa Subscribed

    Nov 2, 2003
    506
    Chas SC
    Full Name:
    Charles Perry
    Wow! A lot of weak information moving here. My 98 spider has the same problem. The black connector is the one for the motor. If you need to move the seat, you can connect +12V DC directly to the two prongs there. Connecting them in one polarity will move the seat forward, connecting them in the opposite polarity will move the seat backward.

    Your problem is definitely related to the potentiometers. When they break, which is often, the computer can't tell where the seat is and so it won't operate the top. You can replace the potentiometer yourself. The trick with setting them is to move the seat to roughly where the working one is, measure the pot value on the working seat, and then set the replacement pot to the same value using an ohmmeter and then install it. You normally do NOT need the SD1 box to reset the system.

    The potentiometers are available separately from Ferrari for about $350. I have also been told by a reliable source that they are the same as are used in some Jaguars. The Jaguar part is available at an alleged $125. So I would take the pot to a Jag dealer and see if they can source it without knowing it's from a Ferrari. I haven't done that yet.

    Also, there are known problems with the solder joints on the computer that controls the top mechanism. I believe this is mounted on top of the motor/reservoir mechanism in the center between the seats. You might remove it and check for broken or cold solder joints.

    The best solution so far is to contact Jeff at Performance Motorcars of NC - (336) 241-3451. He has re-engineered the potentiometer so that they won't break anymore. Basically you ship him both of your seat tracks and your computer. He will replace both pots with the upgraded unit and check the computer for solder problems. Then he sends everything back to you preset. You just re-install tracks and it should work without dealer re-calibration. He's not cheap ($750/seat, no charge for computer) but it seems to be a solid fix. I haven't done this with mine yet but will.

    The 355 is a great car, but you will continue to be deeply disappointed with it if you expect the build quality of a Nissan.
     
  11. Merdav

    Merdav Formula Junior

    Apr 11, 2004
    980
    The seat potentiometer sounds like the problem. Last week I took my out, (it had just been install at the dealer 5 weeks earlier) opened it myself, did a little upgrade myself, it is better than new. If your a little handy and patient is it very simple, ironically there are about $2.00 worth of parts inside. The engineering is two steps below my kids Power Wheels scooter. I will help by phone if you want to do it yourself, the part is a joke and charge to repair or replace the potentiometer is a bigger joke. -MICHAEL
     
  12. Merdav

    Merdav Formula Junior

    Apr 11, 2004
    980
     
  13. 1975gt4don

    1975gt4don Formula Junior

    Nov 5, 2003
    665
    Peoples Rep of CA
    Full Name:
    Smog Exempt
    Putting power seats in an F-car is a bigger joke. All of these relays and motors all add up.
     
  14. Merdav

    Merdav Formula Junior

    Apr 11, 2004
    980
    It's only in the 355 spider, and there is actually a decent reason for it with liability to damaging the soft top.
     
  15. PBRacer

    PBRacer Karting

    Nov 3, 2003
    154
    Virginia
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    Stan
    Is this "upgrade" something a not so technically mechanical person can do?

    How difficult is taking out the seats and putting all this stuff back together?

    Stan
     
  16. Merdav

    Merdav Formula Junior

    Apr 11, 2004
    980
    A decent amount of mechanical ability, and a decent hand tools set is a must.
     
  17. PBRacer

    PBRacer Karting

    Nov 3, 2003
    154
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    Stan
    Got plenty of generic hand tools, not much in the specialty area. No way to lift the car or get under it if that is required to release the seats.

    Stan
     
  18. Merdav

    Merdav Formula Junior

    Apr 11, 2004
    980
    Take the 4 allen bolts off, lean the seat over, disconnect to 2 wires, remove seat, put upside down(on a blanket), slide down the friction washer so the spline shaft clears the pot, small allen key remove pot. Now you ready to start!
     
  19. PBRacer

    PBRacer Karting

    Nov 3, 2003
    154
    Virginia
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    Stan
    That sounds easy enough?

    I'll give that a shot


    Stan
     
  20. cgperry

    cgperry Formula Junior
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    Nov 2, 2003
    506
    Chas SC
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    Charles Perry
    Getting the seats out is pretty easy. No lift or under-car access required.

    It's just four bolts - one on the front of each seat track and one on the rear of each seat track. Just move the seat all the way forward to take out the rear bolts and all the way rearward to take out the front bolts. Hand tools are fine. The only catch is if your seats won't move because of the electrical problem. In this case, you need to get at the connector under the seat and apply 12V directly to the motor as I described above to be able to move the seat and expose the bolts.

    Once the bolts are undone, just unplug the two quick-disconnect electrical connectors and take the seat out of the car. To remove the seat tracks for shipping, turn the seat upside down so you can get at the bottom (put something down to protect the leather). The track/motor mechanisms should be held to the seats with just four Allen head bolts. Take these off and you're ready.

    Jeff did tell me that the Allen heads holding the tracks to the seats were generally put on by 800lb Italian gorillas and are difficult to break loose. He recommends against hand tools because it's easy to strip the inside of the Allen head before it breaks loose. He recommended using an impact gun to do it. I'm sure you can do it either way, but be careful if you do it with hand tools so you don't damage the bolts.
     
  21. PBRacer

    PBRacer Karting

    Nov 3, 2003
    154
    Virginia
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    Stan
    Thanks for the info, i'll try that.

    Stan
     
  22. PBRacer

    PBRacer Karting

    Nov 3, 2003
    154
    Virginia
    Full Name:
    Stan
    Thanks for the info, i'll try that.

    Stan
     
  23. Merdav

    Merdav Formula Junior

    Apr 11, 2004
    980

    The bypass emergency switch on the center tunnel will move the seat any time.
    You cant fit an impact gun in place , use the right size allen key, put a 3/8 extenstion bar BACKWARDS on the allen wrench, the will loosen right up.
    When you have the bad pot in hand PM me and I can talk you through the repair by phone-MICHAEL
     
  24. PBRacer

    PBRacer Karting

    Nov 3, 2003
    154
    Virginia
    Full Name:
    Stan
    Thanks for all the great input. I will PM you once i have it out and in hand


    Stan
     
  25. Merdav and I have been chatting off and on about this subject. Perhaps a bit of my input will interest folks.

    First off, I obtained the so called "Jag" position sensor from one of the Ferrari dealers. The model is JLM21117. The device has the same outer shell, but a different gear set inside- it's yellow instead of the black set inside the F-part. The potentiometer inside is 4k instead of the 4.7k Ferrari part. Most important, the Jag part sweeps the pot in 5 turns of the drive and the F-part sweeps in about 15 turns. I assume the drive shaft in the 355 rack turns more than 5 turns from front to back so I have no idea how the Jag part would work... Maybe there are different Jag parts and I got the wrong one?

    But... here is an interesting option. If you buy the $100 Jag part, you can pop open the halves, then pull the little clutch assembly that goes bad and move it over to the original Ferrari part. It's actually just a little white plastic ball socket thingy. They just wear out or become fragile and break. I also used just a touch of 220 grit sand paper on the ball joint to increase the friction a bit.

    This little clutch is interesting becuase is basically allows the drive to continue turning when the wiper reaches the end of the pot. So, one does not need to set the pot at a specific point during installation. Just put it in. Then, I ran the seat all the way forward and all the way back using the emergency switch to set the potentiometer. Finally, disconnected the battery for about 10 sec. or so and turned it back on. Everything works fine.

    Some things to consider:

    #1 Taking the seat out is a breeze. Just make sure you cover everything around the seats in thick towels and get a friend to help lift it so you don't scratch anything.

    #2 When removing the seat position sensor, it is not necessary to move the friction washer near the small transmission. Just remove the single screw holding the position sensor, the single screw holding the transmission, then pull the transmission forward of the shaft it's on and flex it away from the shaft. It's other black shaft is very flexible and will allow this to work- really! Then, pull out the silver drive shaft and slide the position sensor off. The hardest part is getting the Torx screwdriver in the right position to get to the screws.

    #3 Just in case, I marked the pcs. with a Sharpie before pulling everything apart, but nothing really gets moved when you do this.

    #4 This entire effort took me about 1.5 hours, most of that time was spent discovering how to take the position sensor out and continually washing grease from my hands!

    This was a fun project and I encourage you guys to try it!!!


    One final note: I starting chatting here about 6-years ago. The community was MUCH smaller then. Although I don't always agree with some of the strange off-topic threads, this is still a great place. It's nice reading all of the new and diverse opinions from all of you! I hope to see a number of you in Monterey this year!
     

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