355 AirCon | FerrariChat

355 AirCon

Discussion in 'Technical Q&A' started by matt_comreco, Jul 25, 2007.

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  1. matt_comreco

    matt_comreco Rookie

    Jun 27, 2007
    5
    Hi. Had my 96 355 spider for 7 months now. No problems it’s just so awesome.
    I have one niggle that I am sure is partly down to the fact it’s a Ferrari and something is actually wrong.

    When I set the heating controls to hot and press the stop button and its on ‘0 fan’, not 'aut' and lets say pointing to the screen, I get nothing from the heating vents. When I first got the car at the beginning of the year I would get a trickle of heat when I first drove, but when I pulled over, switched off and re-started it, nothing. Turning the fan position to blow does bugger all too even on a cold setting.

    When I press the stop button I hear a click under the dash, which I suspect is some relay or something shutting the AC off? The stop button also lights up, suggesting that there is power to the heating control. But this should then allow none AC mode to work, hot and outside cold to be blown in.

    As the UK is experiencing very iffy weather at the moment there is a need for heating and cold AC on an almost daily basis and its starting to somewhat dampen each ride (unless the sun is out and the roof is down and there are no complaints). Too hot with the roof up and steamed up windows when pissing down.

    Everyone keeps telling me it needs re-gassing (although these people have never owned a car with AC, never mind one with a Ferrari, you know the ones), but I am confused as to why no heat + blowers in the stop position.

    Before I spend money on a re-gas is there anything else it could be?
     
  2. MManzonelli

    MManzonelli Karting

    Nov 4, 2003
    82
    Columbia, IL
    Full Name:
    Mark Manzonelli
    First I want to make sure you are operating the system correctly. For EITHER the heat or the AC to function, the "STOP" button should be OUT which is on. This will give you either heat or AC depending on the time of year. It is possible when you are in heating season the Compressor will run. It is just the way the F355 system works.

    Let's say it is warm outside and you have the "STOP" button OUT. Turn the temperature dial all the way down cold to the blue dot (US Car is what I have). Turn the fan to "4". Set the distribution dial to the "face vents". You should get cold air and you should hear/feel the compressor running. It should not cycle. If it does cycle you could be low on refridgerant. When it cycles off, most likely you are hitting low pressure which is sensed by a low pressure switch. This saves the compressor from damage. You will most likely need a "re-gas" (more refridgerant). If it does not come on at all, you could be either out of refridgerant (due to a leak) or you have a bad compressor, bad electrical, etc.
    For extra cooling, you can press the recirculate button in this will take the cold air from inside and recondition this air versus taken it from the outside.

    For the heat mode, the "STOP" button will STILL be OUT. Now turn the dial all the way to RED (Hot). Keep the distribution to "Face" (you can always move to floor or defrost on either AC or heat) and you should have HEAT coming from the vents. The compressor could still run.

    If you put the "STOP" button in, the system completly shuts down.

    I hope this helps...

    Mark Manzonelli
    1996 F355 Spider
     
    Mike Morrissey likes this.
  3. matt_comreco

    matt_comreco Rookie

    Jun 27, 2007
    5
    Mark,

    thanks. i try all of this and i get nothing. no compressors, no cold and no hot (or at least no difference when i place my hand over the vents).
    i think that i will go with a regas as i cannot find out in the history when it was last done. i also suspect that it was not used for a long while before i got the car.

    will let you know what sorts it out.

    Matt
     
  4. f355spider

    f355spider F1 World Champ
    Owner Rossa Subscribed

    May 29, 2001
    17,913
    USA
    Matt, are you SURE you followed Mark's instructions, AND read the owner's manual? You should be getting heat, regardless of the AC charge or not. Regassing will have no effect on heat....if you are not getting heat, then either you are not using the control correctly, or you have a fault in the control panel.

    Can you explain what setting you have the controls at, when you get "no heat"?

    Try this...set the fan control on "3"...the "stop" button out (not depressed), the temp control at the highest setting, and the vent control set to the forward facing vents in the dash, and have the car at operating temperature. You should get some heat. Then, with all the controls left the same....turn the temp control all the way to the coldest setting, and you should eventually get cold air.

    What is happening?
     
  5. matt_comreco

    matt_comreco Rookie

    Jun 27, 2007
    5
    i have read and re read the owners manual and followed Marks instructions.

    i have the car out with me today and will try again when i have got it warmed up. prehaphs i am being too impatient with it!
    but what struck me was that earlier in the year i had the settings to stop out, red dot setting and blowers on 0 and front vents open and i would get heat (allbeit faint) when it first started to warm up, but when i stopped (probably for gas!) and resumed the journey the heat would not return until driven from cold again. that stopped after a few weeks.
    thats why i Interpreted the manual to say that the stop button kills the AC and just relies on the natural cold/hot air flow.

    there appear to be no problem with the cooling of the engine as all gauges read spot on.

    i have sat in the car with the manual and worked through it with engine running and hood up, down etc.

    Matt
     
  6. f355spider

    f355spider F1 World Champ
    Owner Rossa Subscribed

    May 29, 2001
    17,913
    USA
    Even though your car is not overheating, I would still double check your coolant level (when cold). It should be about 8 cm or so from the top of the filler neck. Low coolant could prevent the coolant from going through your heater core.
     
  7. lusso64

    lusso64 Formula 3

    Apr 12, 2004
    1,535
    Simi Valley
    Full Name:
    David
    This is to be expected. The fan is at 0 - zero, which means off. If the STOP button is down, then it is "STOPped". Again, I would not expect it to work.

    In the 0 fan position, you will get _some_ air when driving simply because the car is moving through the air itself and some finds it's way through the system. Stopping the car stops the airflow as you described.

    When the stop button is pressed, any change of the temp dial will have no effect, but the water pump that pumps hot water to the heater core will also stop. Hence the warm air experienced due to natural airflow will eventually be cold. When the car is warming up from cold, and the system is set to "STOP" there may be some initial warmth due to convection in the cooling system causing warmish water to flow through the heater core.
     
  8. spaghetti_jet

    spaghetti_jet Formula Junior

    Jan 5, 2005
    846
    Europa
    Full Name:
    Bob
    Matt,

    given that you're using all the right settings here are a couple of points that might be of help:

    "Gas".
    You talk about "re-gassing". If you're talking about refridgerant "gas" (it actually goes in as a liquid) then this is only needed for cooling with a/c. A quick check to do straight away is to open the front bonnet, lift the access patch above the right hand wheel and you will see the A/C drier/filter. It's directly next to the washer fluid bottle. On top of the drier there is a tiny spy window (it might be slightly covered in paint). The spy glass should be dark in colour, if it's clear then you have air in there. If it's dark then there's a fair chance that you're OK for refridgerant. If you do go for a re-gas then make sure the person knows what they are doing because as well as the refridgerant you need to add the right quantity of lubricant for the pump. My suggestion would be a full evac, fit new drier, leak test then re-gas with oil.

    "Heat"
    Despite the fact that on the 355 you need to have the A/C "stop" out the heating of the cabin is separate from the air conditioning in that you take heat from the engine coolant regardless of whether the A/C is charged or not. However, the 355 is different from most "run-of-the-mill" cars in that there is a small electric pump behind the dashboard that pumps the coolant to/from the engine. If you can ascertain that the fuses are OK then you should, as already suggested, check that there's enough coolant in the expansion bottle. If there is then you can remove the carpet trim in the front luggage well bulkhead and you will see the pump and pipes. Check they get hot and that the pump is running. You can do the usual checks to see if there's voltage reaching the pump. You should also check the recirc flap. Try disconnecting the recirc motor connector and see if the system starts to function (the recirc flap solenoids can often get stuck/sieze/shaft damages).

    Other potential issues could be the control panel, the cabin thermostat or the electronic control module, but if I were you I'd start with the absolute basics. It's actually a pretty straightforward system by modern standards.

    Good luck,

    Bob.
     
  9. matt_comreco

    matt_comreco Rookie

    Jun 27, 2007
    5
    Cheers guys.

    i have checked the coolant on a very regular basis as i thought that this might be the problem. it is well within the limits and even bled the system to ensure that no air was trapped.

    as in the heat thing (and i know its different from the run of the mill) i would have expected something when driving with the stop off and the fan to 0 and red dot selected as its just a convection of warm water flowing round. but as bob points out its not as simple as that.

    i will look at the things he points out and report back

    Matt
     
  10. stevew3765

    stevew3765 Formula Junior

    Oct 27, 2012
    716
    Tulsa, Oklahoma USA
    Full Name:
    Steve Wool
    #10 stevew3765, Jun 27, 2014
    Last edited by a moderator: Sep 7, 2017
    Hi is this the spy glass with the darkness that's supposed to indicate that there is refrig in there? My ac comp won't engage or do squat! I changed the hidden fuse already so just going down the list. Next will be the compr I guess. Thanks I don't see where I can attach a pic here. I will post it in the ac thread in the tech q and a section...
    Image Unavailable, Please Login
     
  11. spaghetti_jet

    spaghetti_jet Formula Junior

    Jan 5, 2005
    846
    Europa
    Full Name:
    Bob
    yes, that's the spy glass. It looks good, as best you can tell from a photo.

    One check that you can do at home is to see if voltage is reaching the A/C compressor.

    On the front of the compressor is a clutch which is engaged with a 12v feed. Sometimes the wire can fray internally due to vibration (i.e. looks ok from the outside, but open circuit inside the insulation). If you can manage it then check to see if there is voltage in that wire and at the plug into the compressor. If I remember correctly you can do this from under the car.

    Check it when it's running, and turn the A/C on and off to test the voltage.

    If this circuit is energised and the A/C clutch doesn't engage it tells you that refrigerant level is OK and the problem is in the compressor/clutch because that circuit is only energised if the system is charged with sufficient gas.
     
  12. stevew3765

    stevew3765 Formula Junior

    Oct 27, 2012
    716
    Tulsa, Oklahoma USA
    Full Name:
    Steve Wool
    Thank you. I will try that. btw. That pic was taken when the car was no running. If it matters as far as being able to tell anything. IN other words. If the car was running, would I be able to see circulation in the spy glass?
     
  13. spaghetti_jet

    spaghetti_jet Formula Junior

    Jan 5, 2005
    846
    Europa
    Full Name:
    Bob
    no, the glass should stay dark all the time. If you see bubbles in there or milky looking it's an indicator of a leak. But since the compressor isn't running, from what you describe, then the system isn't circulating anyway and unlikely to change even with the engine running.

    Anyway, before spending big bucks on compressors, clutches or what-not, you should check out the basics like fuses, power etc. but in the end the only real way to diagnose is to take it to a place that does A/C, who knows what they're doing, and get some guages on there to read the hi side and lo side pressures.

    Any decent A/C specialist is fine, doesn't have to be Ferrari specific.

    All the specs are in the WSM if I recall correctly.

    Saludos, Bob.
     
  14. stevew3765

    stevew3765 Formula Junior

    Oct 27, 2012
    716
    Tulsa, Oklahoma USA
    Full Name:
    Steve Wool
    Thank you Bob...
     
  15. pnicholasen

    pnicholasen Formula 3

    Jan 14, 2011
    1,357
    South of Philly
    Full Name:
    Paul Nicholasen
    If the 355 is like my 348, the pressure sensor is on top of the dryer, so if you can't hear the "click" of the A/C compressor clutch engaging when you hit the A/C button, you can try shorting across the connector plug and see if you get a click when you hit the button. You can only engage it briefly, because if it is low on Freon, it's low on oil too, and you don't want to kill your compressor. If it does click, then it's probably low on Freon ( or whatever is in it) and needs a refill. If still no "click" try to find the little wire that goes to the compressor clutch down under the engine. if you tap into that wire and run a + 12 volt wire into it, you should hear that "click" engaging the electromagnetic clutch. If still nothing, it's either a bad clutch or compressor.
     
  16. Mozella

    Mozella Formula Junior

    Mar 24, 2013
    905
    Piemonte, Italia
    Do a Google search about automotive A/C and you'll find many good articles on the refrigeration cycle. At the rest the system is full of gas and the sight glass will look empty. Typically the sight glass is located in the top of the receiver-filter-dryer. That component is installed between the condenser and the expansion valve.

    When the compressor starts it will turn the gas into a hotter, high pressure gas. When this gas is cooled by the condenser it turns into a warm high pressure liquid. After that it flows through the receiver-filter-dryer and on to the expansion valve and evaporator where the liquid flashes back into a gas absorbing a huge amount of heat; i.e. "producing cold". It is this phase change which is the key to the refrigeration cycle and that requires a special gas like 134a or R-12 which can go through this phase change at reasonable temperatures and pressures.

    So, if you observe the sight glass immediately after the compressor is turned on, within a few seconds you should see the empty sight glass start filling with liquid, then you might see a series of bubbles, and very quickly you should see pure liquid. Some sight glasses are easier to read than others and it's not always obvious if you're looking at pure gas or pure liquid. That transition period immediately after switching the system on only takes a few seconds with a properly operating system. It may be educational to observe a good system before troubleshooting one which is not working correctly.

    Sometimes a tiny bubble is trapped on the edge of the sight glass and you can see the movement of the liquid as this bubble jiggles around. Or you might just see pure liquid and it can sometimes be very difficult to know what you're looking at. That's why watching the sight glass as you switch on the compressor can give you useful information and avoid confusion.
     
  17. Mozella

    Mozella Formula Junior

    Mar 24, 2013
    905
    Piemonte, Italia
    Are you sure?

    The system is full of gas at start-up; consequently, the sight glass should be full of gas; i.e. it should look empty. Right after start-up, the sight glass will show liquid refrigerant within a few seconds, usually producing some bubbles during a short transition period. These bubbles will all but disappear in a short time measured in seconds.

    Some sight glasses include various lenses and background images to make things easier to see. Others are quite hard to read and it's possible to confuse gas with a clear liquid . But all of them should show the transition from gas to liquid immediately after compressor start-up IF the system is working properly.
     

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