Fluctuation with AC Fan Speed in 456M | FerrariChat

Fluctuation with AC Fan Speed in 456M

Discussion in '456/550/575' started by pchop, Jul 29, 2025 at 10:49 AM.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. pchop

    pchop F1 Rookie Rossa Subscribed

    Joined:
    Jun 12, 2002
    Messages:
    2,670
    Location:
    Usually NY often elsewhere.
    Full Name:
    John
    Fan speed is set at level 4 (max), and while driving, it suddenly dropped to level 3. Speed will occasionally fluctuate while the car is moving. Anyone seen this before? Would it be the fan control module or the motor?
     
    pchop, Jul 29, 2025 at 10:49 AM
    #1
    vraa likes this.
  2. forgottenkeys

    forgottenkeys Rookie

    Joined:
    Mar 1, 2016
    Messages:
    12
    It happens on mine too (456M). AC worked fine for years and for no obvious reason it changed and the fan speed now fluctuates - sometimes full power sometimes lower. I haven’t had this checked out yet as it’s not on my top 5 things to fix this year but I hope you find what the underlying failure is.
     
    forgottenkeys, Jul 29, 2025 at 11:05 AM
    #2
    vraa and pchop like this.
  3. pchop

    pchop F1 Rookie Rossa Subscribed

    Joined:
    Jun 12, 2002
    Messages:
    2,670
    Location:
    Usually NY often elsewhere.
    Full Name:
    John
    Anyone? 550/575 has similar (if not the same) fan controls. I recall there's was a thread of this issue.
     
    pchop, Jul 30, 2025 at 9:37 AM
    #3
  4. Qavion

    Qavion F1 World Champ Silver Subscribed

    Joined:
    Feb 20, 2015
    Messages:
    14,337
    Location:
    Sydney
    Full Name:
    Ian Riddell
    It probably isn't the fan, but you can prove it by bypassing the ECU and fan control module with some effort.

    Locate and disconnect the smaller plug (of two) on the fan controller in the passenger footwell on the right hand side of the evaporator:

    Image Unavailable, Please Login


    Another shot here (550):

    Image Unavailable, Please Login

    On the non-controller side of the smaller connector, short out the blue and black wires (sockets/pins?).

    The fan will run continuously at high speed.


    Image Unavailable, Please Login
     
    Qavion, Jul 30, 2025 at 5:56 PM
    #4
    pchop likes this.
  5. pchop

    pchop F1 Rookie Rossa Subscribed

    Joined:
    Jun 12, 2002
    Messages:
    2,670
    Location:
    Usually NY often elsewhere.
    Full Name:
    John
    Thanks, pal, for always being resourceful! If you are in NYC area, we'll break bread.
     
    pchop, Jul 30, 2025 at 9:51 PM
    #5
    Qavion likes this.
  6. tazandjan

    tazandjan Three Time F1 World Champ Lifetime Rossa Owner

    Joined:
    Jul 19, 2008
    Messages:
    39,189
    Location:
    Clarksville, Tennessee
    Full Name:
    Terry H Phillips
    A lot of ocean (and land) between NY and Australia.
     
    tazandjan, Jul 30, 2025 at 11:09 PM
    #6
    Qavion likes this.

Share This Page