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355 A/C - Heater Fan not working

Discussion in 'Technical Q&A' started by Jbuffa, Feb 23, 2004.

  1. Jbuffa

    Jbuffa Rookie

    Nov 7, 2003
    28
    Atlanta
    Full Name:
    Joseph Buffa
    I was driving home the other night when my heater stopped blowing. It seemed at the same time there was a small hesitation in the motor, like I would have lifted the throttle. Anyway, I checked the only fuse in the manual for the A/C System and it was fine. I did not see any other fuses or relays related to the Blower Fan or the A/C System.

    Are there any suggestions on what else to look for? I would like a chance to fix it myself before I take it into service.

    1995 355

    Thnaks,
    Joseph
     
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  3. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    19,497
    Texas
    Full Name:
    Steve Magnusson
    (Just speculating, but) Most likely your blower system uses a power transistor for blower motor current control. Since the blower motor current is large, these power transistors run hot and are usually mounted somewhere in the blower air stream output/vent on a heatsink. IME they don't mention it or its location in the OMs (only the WSM -- and if it exists, it might be called "power transistor" in the SPC). Sorry I can give any real information, but you'll need the 355 technical references to investigate...
     
  4. Ferrari_tech

    Ferrari_tech Formula 3

    Jul 28, 2003
    1,527
    UK
    Full Name:
    Malcolm W
    Joseph,

    You well may have to wait until you have the car serviced as there are several components that could cause you system failure - proper diagnosis with the aid of a SD2 tester is the most effective way of finding the problem.

    The most common cause of failure is the power unit (as said, it replaces the power transistor fitted on earlier cars), the other component is the ECU that monitors and controls the entire heating / A/C system.

    Should you need them hear's the part numbers :-

    Power unit 63307200
    ECU 64324800

    Of course it may well be a simple wiring fault, just takes time tracking down.

    Good Luck


    MW
     
  5. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,034
    The Brickyard
    Full Name:
    The Bad Guy
    Hey Joseph

    I'm not sure about the 355's, but the equipment is about the same as the 348's. I'm pretty sure Ferrari used the same heating units for the 355's. Anyhow, on my 348 you have to take off the top part of the trunk liner to see the blower box for the a/c & heater. The blower unit is on the passenger side of the trunk. Once you have the top part of the trunk liner off you will be able to see some relays and plugs. There are two of them mounted on the side of the blower box, you can see them from the passenger side of the car. Not the ones that are mounted to the wheel well, those are fuses and there are four, but the two on the side of blower unit, on my car they are green. I had one of them go bad on me and the blower doesn't work now. You can see were they were shorting out, the plastic looks burnt. Anyway, try giving that a look to see if there is any sign of them shorting out. Or just make sure that everything is plugged in properly. Hope I was some help.
     
  6. Jbuffa

    Jbuffa Rookie

    Nov 7, 2003
    28
    Atlanta
    Full Name:
    Joseph Buffa
    Ernie,

    After removing the carpet panels next to the blower, I found that the fuse "Green 30" next to the two relays mounted on the Blower, was completely melted. I wonder if the "30" is too strong of a fuse for that position. Do you know what size fuse is sopposed to be there? Anyway it works now, but I'm keeping an eye on it.

    Thanks,
    Joseph
     
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  8. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,034
    The Brickyard
    Full Name:
    The Bad Guy
    You are talking about the little fuse with the (30) stamped on the top of it aren't you? If you are I just looked at mine and I also have 30amp fuse. Glad to here it's working again, but DO keep an eye on it. I'm not sure exactly what fuse you are talking about, but I have an pretty good idea. Anyway what you should do is check for any shorts in the wiring that, that fuse controls. It could be that the bearing in the fan is starting to go bad causing it to hange up, and as a result the fuse pops. Or it could be something else. None the less, keep an eye on it.
     

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