355 5.2 : problem with right fan relay (maybe a bad ground) | FerrariChat

355 5.2 : problem with right fan relay (maybe a bad ground)

Discussion in '348/355' started by Gengis, Sep 11, 2010.

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  1. Gengis

    Gengis Rookie

    Aug 22, 2007
    11
    #1 Gengis, Sep 11, 2010
    Last edited by a moderator: Sep 7, 2017
    Hi,

    I'm facing a problem on my 355 (97, GTB) : from times to times the right fan relay makes a kind of 'clic clic clic'. I can clearly hear it, it comes from the electric panel behind the passenger feet. I recorded the noise with my cellphone, see attachment (you unzip it and play the amr file with vlc).

    When I put the finger on the relay I can clearly feel a kind of vibration (of course the vibration disappears when the noise stops). Changing the relay itself doesn't change anything.

    When the noise starts the interior light flickers a little bit (if it is switched on obviously, or if doors are open). I guess it comes from a bad ground, a ground which is share by interior lamp and right fan relay. Am I right ? Do you know if a such ground exists, and if it does where is it located ? The one behind the electric panel behind the passenger feet is OK so I think it comes from somewhere else... But where ?

    Thanks for your help,

    Cheers
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  2. f355spider

    f355spider F1 World Champ
    Owner Rossa Subscribed

    May 29, 2001
    17,939
    USA
    #2 f355spider, Sep 12, 2010
    Have you tried swapping relays, to eliminate the possibility of a bad relay?

    It could also be a bad fan motor I suppose. The fan motors do require replacement periodically. I replaced both of mine earlier this year, as they were blowing the 30 amp fuses. (as the motors age, they start drawing excessive current) Along with blowing fuses, if you ignore the problem the excess current draw can damage the fuse box/panel.
     
  3. Gengis

    Gengis Rookie

    Aug 22, 2007
    11
    #3 Gengis, Sep 13, 2010
    Hi, when I switch relays the noise (and the vibration) does not move : it still comes from the right fan relay.

    And because the interior light flickers when (and only when) the relay is noisy I think that the problem on the relay is a result of a bad contact, not the cause (unless if interior light depends on the right fan wiring, which I doubt).
     
  4. f355spider

    f355spider F1 World Champ
    Owner Rossa Subscribed

    May 29, 2001
    17,939
    USA
    #4 f355spider, Sep 13, 2010
    How is the fan operation?

    It would not be difficult to test your hypothesis by removing the right side wheel and forward portion of the fender liner and add an additional ground from the fan motor to the chassis. I suspect a bad motor myself, but no telling until futher diagnosis.

    It is also possible you have a problem with the fuse panel itself...
     

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