Fiat hymer b544 1996 step

Discussion in 'Tech/Mech General' started by Laura F, Jul 30, 2016.

  1. Laura F

    Laura F Funster

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    Hi every one,

    When we purchase the van the step was not working, we have just got round to removing the moter and gear.

    The nut had well rounded so it's not going to be easy to separate the to.

    How do I find out what make the step is?

    How do I find out the parts numbers ?

    The is power to the switch, so I am thinking its a gear or motor problem ?

    Any help is welcome, Laura X
     
  2. tonyidle

    tonyidle Funster

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  3. Laura F

    Laura F Funster

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    This is the only pic I have on my phone, I can get some more when I get home later, what part do you need a pic of ?
     

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  4. Wagoneer

    Wagoneer Funster

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  5. mike mcglynn

    mike mcglynn Funster Life Member

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    Hi,Laura if you are doing this job yourself take care as it may actuate with your fingers being trapped in the works so be warned .
     
  6. scotjimland

    scotjimland Funster Life Member

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    not necessarily .. the switch has a pcb with two relays which may be the problem. It is a Hymer part ..


    I had problem with mine, also a Hymer.. it has an Omnistor step.. it was my switch that was faulty.. full thread here.. http://www.motorhomefun.co.uk/forum/threads/hymer-step-switch-how-much-gulp.106645/



    Just for info. Omnistore Electric Step.

    wiring drawing .. and fault finding


    [​IMG]

    The control switch is a DOUBLE CHANGE OVER SWITCH. (Not a double pole change over as this is subtly different) This switch contains two change over switches, one switch changes over when the rocker is operated in one direction and the other switch changes over when the rocker is operated in the other direction. So it carries out a few more functions than just a simple ON/OFF switch.

    The Omnistep has a permanent magnet motor. This means that if you reverse the polarity the motor will run in the opposite direction. The switch is designed to do this. The motor rotates in one direction to extend and the other direction to retract.

    Nominally 5 amps is the expected working current for the motor. If however you keep your finger on the switch after the step has fully extended or retracted then the motor will stall. Under this condition the current will increase to a significantly higher figure. Sometimes referred to as the “blocking current”.

    The Omnistep has two electrical components, the motor which moves the step and a switch that is OPEN only when the step is fully retracted. At all other times the switch will be closed.

    Firstly the system is designed to retract the step and sound the alarm should you start your engine with the step extended.

    Under this condition the control switch is as shown in switch picture A. Battery negative is connected to terminal 4 of the switch and comes back out of the switch at terminal 5. It is connected to the right hand end of the motor with a RDGN wire.

    When the engine is running the FRIDGE relay is energised from the vehicle alternator D+ terminal. The fridge relay applies 12 volts to both the fridge and also the step relay terminal 86 (coil+) and one side of the alarm.

    If the step is extended then the step switch will be closed. This will provide a negative supply to the alarm causing it to sound, and also the other end of the relay coil (85) causing it to energise.. Now that the relay is energised the fridge supply which is also connected to the relay terminal 87 is routed by the closed contacts to relay terminal 30 and provides a positive supply to the Omnistep motor. The motor will rotate causing the step to retract. When fully retracted the step switch will open, the relay will release, the alarm will go silent.

    With the engine turned OFF the rocker switch can be depressed causing the step to extend.

    Under this condition the control switch is as shown in switch picture C. Battery negative is connected to terminal 4 of the switch and comes back out of the switch at terminal 1. It is connected to the relay terminal 87a (normally closed contact) and comes out of the relay at terminal 30. From here it is routed to the left hand end of the motor.

    A positive supply from the leisure battery enters the switch at terminal 3 via a BNGN wire. This positive supply leaves the switch at terminal 5 which is routed via a RDGN wire to the right hand end of the motor causing the step to extend. When the step has extended you must leave go of the switch or the current will increase to 14 amps!

    With the engine turned OFF the rocker switch can be depressed causing the step to retract.

    Under this condition the control switch is as shown in switch picture B. Battery negative is connected to terminal 4 of the switch and comes back out of the switch at terminal 5. It is routed to the right hand end of the motor.

    A positive supply from the leisure battery enters the switch at terminal 3 via a BNGN wire. This positive supply leaves the switch at terminal 1. It is connected to the relay terminal 87a (normally closed contact) and comes out of the relay at terminal 30. From here it is routed to the left hand end of the motor causing the step to retract. When the step has retracted you must leave go of the switch or the current will increase to about 14 amps!
     
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  7. tonyidle

    tonyidle Funster

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    Further to sj reply above - if you can access the two wires connected to the motor (as you appear to have already removed it) you can test it by connecting to a 12v battery. It doesn't matter which way round the wires are connected as reversing them simply reverses the motor. Doing this test would tell you immediately whether the motor is working or not.
     
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  8. Laura F

    Laura F Funster

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    Thanks every one for your reply, will
    Test the moter in the morning now all the major dirt has been removed
     
  9. Laura F

    Laura F Funster

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    Ok all, motor has been tested and is dead ! I have had a breif search and it looks like a new motor is hard to find?
     
  10. scotjimland

    scotjimland Funster Life Member

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  11. Wagoneer

    Wagoneer Funster

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    Check where the 2 wires connect to the motor. There should be an access point where you can get to the carbon brushes. The brushes may be worn and not making contact with the commutator (this contact point is essential to make the motor rotate).

    PS. Like the new avatar
     
  12. Laura F

    Laura F Funster

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    Think the husband will be happy with the new photo lol

    I have had a look omnistor website and can not see a part that looks like the old gear or motor parts.

    I don't think it has run in years, I would not bother but the first time using the van we nearly drove off and left the steps behind x
     
  13. Wagoneer

    Wagoneer Funster

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    Hubby looks a sweaty - but obviously you are the brains.

    So, presumably you can retract the step, albeit with a bit of manual dexterity ???
     
  14. Laura F

    Laura F Funster

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    Yep, we can open and close the step with a bit of messing. It was extremely stiff and we recon it's not run for a couple of years x
     
  15. Wagoneer

    Wagoneer Funster

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    Yes, I found that the step mechanism can get stiff & squeaky over time. There are some nylon/plastic washers at the pivot points which are supposed to help with the smooth operation of the step. However, when the pivot points do eventually stiffen up, some people lubricate them with oil. The oil causes the nylon/plastic washers to swell and makes the situation worse. If you need to lubricate the pivot points, ONLY use silicone spray - that's what my Hymer dealer used.

    Hope you get the motor sorted soon :X3:
     
  16. tonyidle

    tonyidle Funster

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    Depending on your mechanical ability (and/or the price of a replacement) you would be able to resurrect the motor using parts (or even the whole motor) from car window mechanisms. Here's an example off a BMW Z3 (as it happens):

    Untitled.jpg
     
  17. Laura F

    Laura F Funster

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    Wow I wish I had that mechanical ability ! I am handy but not that handy! I am stuck trying to get the rounded nut off so I can separate the motor and gear !

    We have covered the step on WD 40!!! I will get some hot soapy water on it and some silicone spray X
     
  18. scotjimland

    scotjimland Funster Life Member

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