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Another 456 Power seat question

Discussion in '456/550/575' started by Tricolore999, Dec 4, 2020.

  1. Tricolore999

    Tricolore999 Rookie

    May 27, 2018
    36
    Colorado
    Hi all,
    I have read through a few of the power seat threads and absolutely loving the information.
    I'm hoping maybe someone can point me in a direction: My 456M driver seat occasionally only scoots forward a few mm's (the fore/aft motor works fine, as it reverses OK). Possibly the fold forward switch is going out?
    Tried checking and pulling the fuses, nothing yet.
    Thanks in advance for saving me so much time :)
     
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  3. Qavion

    Qavion F1 Veteran
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    Feb 20, 2015
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    Ian Riddell
    So the seat won't move forward with either the switch on the side or with the easy entry system? Do the seat memory switches allow movement when they are used (when the seat is malfunctioning).

    By "fold forward switch", do you mean the easy entry switch, the back tilt switch or a specific microswitch?

    There was a recent discussion on the complexities of the seats. We still haven't got a complete wiring diagram or understanding of the system, but we're slowly improving our understanding of it.

    What position is the seat in now? Is it going further and further back, or is the intermittency allowing you to move it forward?
     
  4. Tricolore999

    Tricolore999 Rookie

    May 27, 2018
    36
    Colorado
    Seat moves the same with memory, just not forward (when being finicky) with switches or easy entry. I can move it forward slowly by switching repeatedly (like mm by mm), and moves back properly at all times.

    From the lengthy thread I read, it sounds like it could just be the seat ECU - I saw another user was able to unplug it and reset it. I thought pulling the fuses might help, but it did not.
     
  5. Qavion

    Qavion F1 Veteran
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    Possible. I guess you could try swapping the ECUs.

    Do you mean the fuses under the seat (that I've been told about)? I haven't figured out how the underseat fuses are wired in. They're not shown in any of the diagrams, so I don't know what they affect.

    What happens on the 456M when you disconnect and reconnect the battery? Do you have to reprogramme the seats?
     
  6. Tricolore999

    Tricolore999 Rookie

    May 27, 2018
    36
    Colorado
    I'll try the battery tomorrow. I tried the 2 x fuses for driver seat under the passenger footwell.
    Let me ask a starter question: How to access the ecu or under the seat at all? Do I need to unbolt seat? No way my hand, let alone a tool, fits under there.
     
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  8. Qavion

    Qavion F1 Veteran
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    #6 Qavion, Dec 4, 2020
    Last edited: Dec 4, 2020
    I was wondering that myself. Perhaps @456enthusiast knows?

    I see a metal plate covering it to add to the difficulty.

    If you removed the fuses in the footwell, then that should be the same as disconnecting the battery (so disconnecting the battery is essentially a waste of time).
     
  9. 456enthusiast

    456enthusiast Karting

    Jul 23, 2011
    98
    UK / Italy
    Hi,

    6 bolts to remove the seat (2 in front, 4 in the back). Make sure you properly unplug the ECU cable before lifting the seat.
    Guess swapping the ECU would be the first thing to do to troubleshoot.

    Ian, i read about the under seat fuses too, though I've found none under my M GT seats (maybe they can only be found on earlier models).
     
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  10. Qavion

    Qavion F1 Veteran
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    Can you simply tilt the seat forward after loosening the bolts to allow you to access the ECU or do you have to take the seat out?
     
  11. Tricolore999

    Tricolore999 Rookie

    May 27, 2018
    36
    Colorado
    Not really. You could remove them and then tilt it - check attached pic, this is what they look like.

    I'm quite sure its the rear entry switch now, As I'm fiddling around under the seat with the seatback forward, it's scooting around OK
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  13. Tricolore999

    Tricolore999 Rookie

    May 27, 2018
    36
    Colorado
    Well, I stand corrected: Unplugged the seat ECU, plugged it back in, cycled the ignition and BOOM it works in all directions very nicely. So, pulling the fuses does not do the same as pulling the ECU (I guess it's power runs on another circuit).

    Also, you CAN access the ECU from the back without removing the seat, but it's not easy. Will attach a pic momentarily
     
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  14. Tricolore999

    Tricolore999 Rookie

    May 27, 2018
    36
    Colorado
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  15. Qavion

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    Well, there are few possibilities. There is only one power source (with the ignition off), but.... resetting the plug could have cleaned up some corrosion on the plug pins. It could have been based on the time the fuses/plugs were disconnected (capacitors may need to be discharged to reset things). If you disconnected the plug with the battery not disconnected, there could have been a small spark which upset the circuits (although usually to the detriment to the ECU).

    Thanks for the pics. It's good to know it can be done. I'll be sure to recommend the plug reset if others have this problem.

    Cheers
     
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  16. Qavion

    Qavion F1 Veteran
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    Well, there are a few possibilities.

    Sorry, haven't had my morning coffee yet.
     

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