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Air recirculation door issues

Discussion in '456/550/575' started by AVIMAX, Jan 13, 2021.

  1. AVIMAX

    AVIMAX Formula Junior

    Aug 5, 2014
    550
    Toronto
    Full Name:
    Ryan
    #1 AVIMAX, Jan 13, 2021
    Last edited: Jan 13, 2021
    The doors for the recirculation function in the 550's evaporator unit seem to be quite fragile with age, at least in my experience. Two years ago I had an issue with the blower motor in my car. The fan regulator blew, I replaced it (not fun to do in the car) and then it blew again and the the blower motor started to make noise. Figuring there was an issue with the blower motor and you can't buy it separately, I found a used evaporator unit and had it delivered. Once the original evaporator unit was pulled from the car, it was clear that one of the recirculation doors had broken at the hinge and the foam and covering from the door was sucked into the fan and ended up burning out the fan regulator. Long story short, I probably could have fixed the unit, but the used one went in and I kept the original for spare parts and all was good. Fast forward two years and now while I have the dash out of my car, I noticed that once again, one of the recirculation doors is broken, and the motor that moves it has forced the door into a position that closes off the blower motor from getting any air. This explains why the vents on the passenger side last summer were very weak. I've freed the door, disconnected it from the arm that moves it, and plan to fasten the door in place in the fresh air position and leave it disconnected from the arm that moves it. I can do all this with the evaporator unit in the car. If I ever have to pull the whole think out again, I'll try to fix the door so it moves again. Question is, the motor that moves the door. Do these operate for a finite time to open and close the door, or does the ECU turn the motor on and then wait for some "feedback" from the motors once the doors can no longer move and then turn the motor off. I'm wondering what will happen with the motor no longer connected to the door? Will the motor turn on and then stay on indefinitely? I realize this is something that probably nobody's played with, but you never know. Any guesses?

    I'm including photos of what happens when one of the doors break. It's nice to have the original unit out of the car to play with and problem solve. Evaporator unit with area of recirculation door circled. First unit is the side that is inside the firewall and not accessible without removing the unit. The second photo is the side under the dash and exposed to work on.

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  2. AVIMAX

    AVIMAX Formula Junior

    Aug 5, 2014
    550
    Toronto
    Full Name:
    Ryan
    #2 AVIMAX, Jan 13, 2021
  3. AVIMAX

    AVIMAX Formula Junior

    Aug 5, 2014
    550
    Toronto
    Full Name:
    Ryan
    #3 AVIMAX, Jan 13, 2021
  4. AVIMAX

    AVIMAX Formula Junior

    Aug 5, 2014
    550
    Toronto
    Full Name:
    Ryan
    #4 AVIMAX, Jan 13, 2021
  5. AVIMAX

    AVIMAX Formula Junior

    Aug 5, 2014
    550
    Toronto
    Full Name:
    Ryan
    #5 AVIMAX, Jan 13, 2021
    F456M likes this.

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  6. F456M

    F456M F1 Rookie
    Silver Subscribed

    Jan 8, 2010
    3,022
    Oslo
    Full Name:
    Erik
    #6 F456M, Jan 13, 2021
    Last edited: Jan 13, 2021
    Thanks for sharing.

    I just want to add that the recirculation is very important to get a good cooling with the AC on. Last summer we had about 37 degrees C. in south of France, and my Chevrolet Avalanche did not blow very cold. I re-charged the system with more refrigerant and it started cooling much better. But still, it was not enough to make the car keep a nice chill inside temp. I checked everything up front and cleaned the condenser radiator etc. I talked to some AC experts and they said it is absolutely neccesary to reciculate the air. But my recic button was in and the little LED was on. I thought what the hell, and stopped the engine and turned on the ignition without starting the engine. I pressed the button a few times and heared nothing. I realized that the inlet door did not function at all and was always in the «fresh putside air» position. The actuator is a nightmare to get to, so instead, I put a small piece of wood between the door and the body of the unit so it was 90% recirculating but also let some new air come in. After 2-4 mins the air was super chill and great.

    If you read the manual of our cars, the text shows that the recic door is closed much of the time, but opens up every second minute to make fresh air come into the car. As a consequence of my experiences with my truck and the fact that the V12 gives immense heat from the engine under the cockpit, the need for this door to function might be bigger than what you might assume. Should some of the hinges be lubricated to make them glide more freely? On my car, there is a sound now coming from the flap that was not there before. I hope that the car can keep cold during this summer.
    Thanks
     
  7. AVIMAX

    AVIMAX Formula Junior

    Aug 5, 2014
    550
    Toronto
    Full Name:
    Ryan
    #7 AVIMAX, Jan 13, 2021
    There are 2 doors, one for each side of the car. The door on my driver's side is still intact, so I think I will be OK with jus the passenger side fixed on fresh air. It's definitely better than it was blocking off the fan's intake on the passenger side.
     
  8. Qavion

    Qavion F1 Veteran
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    Feb 20, 2015
    5,220
    Sydney
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    Ian Riddell
    #8 Qavion, Jan 13, 2021
    If it's like the fresh air flap on the F355 with only two wires, the motor is constantly powered in one direction or the other. It just stalls when it hits the endstops. Usually position feedback requires extra wires. Some 355 owners have put microswitches in the circuit to cut power to the motor when the flap hits the endstops. If you're going to jam the door in a particular position and disconnect the linkage to the motor, it might be a good idea to disconnect the motor. I don't know how loud the motor is when it's turning, but it may create an annoying noise.

    By the way, the 456M has two relays and two fuses mounted on the evaporator unit. I believe the 550 has only one relay and two fuses. Is it possible to access these on the 550 without pulling out a lot of the dash (or the entire evaporator unit). Is the fan controller also accessible without a lot of disassembly?


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    i.e. items 18, 20 and 21.

    Would you have any closeups of this area (that the white arrow is pointing to)? Is this where the relay is?

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    Thanks for the pics. Very helpful.
     
  9. Qavion

    Qavion F1 Veteran
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    Feb 20, 2015
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    Ian Riddell
    #9 Qavion, Jan 13, 2021
    Here's a photo (from FChat) of the other side of the evaporator showing the ECU.

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    Is the area above the carpet normally exposed? Do you need to remove any panels to access the ECU plugs?
     

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  10. AVIMAX

    AVIMAX Formula Junior

    Aug 5, 2014
    550
    Toronto
    Full Name:
    Ryan
    #10 AVIMAX, Jan 13, 2021
    I can post a close up of that area tomorrow. The ECU is accessible without removing the carpet. I’ve swapped it out in place before, but you have to move the water valve.
     
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  11. AVIMAX

    AVIMAX Formula Junior

    Aug 5, 2014
    550
    Toronto
    Full Name:
    Ryan
    #11 AVIMAX, Jan 14, 2021
    Ian, photos as requested. The relay and fuses are accessible in the car, the fan controller is almost impossible to replace in the car. 575 WSM says to remove the dash and evaporator unit from the car in order to replace the controller. After replacing the controller myself I know why it is recommended to remove the evaporator. The screw on the top of the controller is almost impossible to access. It was something I never want to do again. If I had to do it again, I'd definitely remove the dashboard to get to it. Well worth the extra hour of work to get the dash out of the way.

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  12. Qavion

    Qavion F1 Veteran
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    Feb 20, 2015
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    Ian Riddell
    #12 Qavion, Jan 14, 2021
    Great to know.. and thanks for the pictures (and the added graphics), Ryan.

    I just wished Ferrari didn't make so many changes between models. e.g. the 456M has two relays in this location. The wiring is still much of a mystery.

    The big fuse is for the blower motor. I'm surprised there is so little mention of it on the forum. Perhaps because the controller is the first thing to fail, not the fan motor. The controller location is definitely a design failure.
     

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