"Air Bag" light, Temp. Gauge + Turbine noise???

Discussion in 'General Motoring' started by petercharlesfagg, Jan 5, 2007.

  1. I am a member of CPUK no.2482 and I own a Peugeot 405 Estate 1.9D XLD
    1996 Turbo.

    I have been posting my queries on the official forum because I did not
    know that this one existed!

    Anyway this is the problem:

    Recently as I drive my "Air Bag" light comes on, the Temp. gauge stops
    working and now there is a strange turbine like sound under the bonnet
    that subsides gradually after switch off. The fuse a 5 amp. in section
    5 in the inside fuse box blows but not every time!

    The fault corrected itself once?

    This time I have driven a couple of hundred miles before it happened
    again, any ideas?

    Regards, Peter.
     
    petercharlesfagg, Jan 5, 2007
    #1
  2. Addendum: The fan noise is precisely that, the cooling fans are at full
    throttle all the time! I have checked through all the fuses both
    in-car and under bonnet and they are OK.
     
    petercharlesfagg, Jan 5, 2007
    #2
  3. petercharlesfagg

    Brian Guest

    Not sure that the air bag light and other things are connected. If you have
    seat belt pretensioners on that model then the connectors for them under the
    front seats are often not too good. Unclip them and reclip with the ignition
    OFF.
    By cooling fans, I understand the fans in front of the rad. If you have air
    con on this model, then there is a Bitron control unit, usually a brown box
    just behind the nearside headlight with a multi connector. Unplug this,
    spray with WD40 and replug. This cured the fans always on on my slightly
    earlier 405. The temp guage is also part of the Bitron circuit.
     
    Brian, Jan 6, 2007
    #3
  4. Brian, thankyou for your response, I was beginning to panic, visions of
    flat batteries etc!

    Pretensioners are not fitted, but I suspect something is amiss under
    the steering wheel cover because I had a battle replacing the
    instrument cluster some weeks ago, speedo drive wouldnt locate!

    As for the fans I will tackle the ideas when I have time off work,
    hopefully the Bitron unit is the cause! It will be a relief, it sounds
    as if I am clear for take off at traffic lights!

    Thankyou again, I will repotrt back in due course.

    Regards, Peter.
     
    petercharlesfagg, Jan 6, 2007
    #4
  5. Brian, took your advice, no difference!

    Cooling fans still roaring away at full blast!

    Any more ideas, I am willing to try anything as long as it doesn't cost
    anything?

    Regards, Peter.
     
    petercharlesfagg, Jan 8, 2007
    #5
  6. petercharlesfagg

    Brian Guest

    I'm afraid I can't help much more.
    Certainly whenever the air con is turned on the cooling fans will run,
    that's the way they designed it.
    Whether a faulty temp sensor could cause this, I don't know.
     
    Brian, Jan 8, 2007
    #6
  7. I'm afraid I can't help much more.
    Brian, I think we are at odds here.

    By the cooling fans I am referring to the radiator fans.

    The "Air Conditioning" is never used because it needs re-gassing and I
    am not prepared to pay for the service, I look upon it as a luxury that
    is not required anyway!

    If I am too hot I open a window, most times the window is open anyway,
    even in the winter!

    Regards, Peter
     
    petercharlesfagg, Jan 8, 2007
    #7
  8. Certainly if you remove the plug from the brown thermostat sensor, this is
    the one controlling the bitrol unit, both fans will run at full speed. Try
    cleaning the contacts on this thermostat and its plug.
    Mike
     
    MICHAEL ROCHE, Jan 9, 2007
    #8
  9. Mike, this is precisely what I have done, removed all 3 contacts,
    sprayed with WD40, reconnected several times to get good contact and
    finally screwed up tight with the same result, fans on full blast!

    Lost for ideas!

    Peter.
     
    petercharlesfagg, Jan 10, 2007
    #9
  10. Follow up:

    I have replaced the water temperature sender, removed, cleaned, sprayed
    with WD40 the 2 other sender connectors on the cylinder head around the
    fuel filter. (What a pain to get to the one behind the filter
    housing!)

    Result: still the same, cooling fans going full blast!

    Anyone any more ideas?

    Peter.
     
    petercharlesfagg, Jan 14, 2007
    #10
  11. petercharlesfagg

    Chris Guest

    Replace it will a new one
     
    Chris, Jan 14, 2007
    #11
  12. petercharlesfagg

    EJH405

    Joined:
    Sep 19, 2022
    Messages:
    1
    Likes Received:
    0
    Well, 15 years later, here's the definite answer:

    Contrary to the electrical schematics of a 405 ph2 with airco (at least the schematics I have), the airbag and one of the supply-lines of the cooling-fan-control-box (Bitron) share fuse F2, indeed 5 amps. If that fuse is blown, the cooling-fan-control goes into safety mode, which is blowing at full power, this is documented behaviour of the control-box. The cause for the blown fuse, and the airbag-light that comes on, is likely a short-circuit in the clockspring under the steering-wheel. That clockspring transfers 12Volt to the airbag unit. Or the cause is a short-circuit of the airbag-unit itself.
    (The airbag-controller is in the steering-wheel too, quite unique design.)

    Thank you for sharing your story 15 years back, now I know that my case was not unique!
     
    EJH405, Sep 19, 2022
    #12
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