348 HVAC panel | FerrariChat

348 HVAC panel

Discussion in '348/355' started by John Glen, Jul 21, 2023.

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  1. John Glen

    John Glen Formula Junior

    Dec 30, 2009
    494
    Victoria, B.C, Can.
    Full Name:
    John Glen Wesanko
    It's the one item on my repair list that continues to elude...Does anyone here have experience with a reputable shop that can diagnose and repair the digital controller ? It does power up but seems riddled with faults ? Thanks, J Glen Wesanko 1990 348 ts
     
  2. ChoonHound

    ChoonHound Formula 3

    May 13, 2022
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    Ditto. My shop is looking at mine again a second time. If you do a forum search you’ll find a post where a member found an engineer to repair his. It can’t be hard. That’s my next step.
     
  3. Ferrarium

    Ferrarium F1 Veteran
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    There is a diagnostic mode on the HVAC panel have you run through that to see what it says? Also if the heat pump in the front bonnet for the cabin heater seizes that can cause the HVAC panel to go haywire and blow caps etc.
     
  4. ChoonHound

    ChoonHound Formula 3

    May 13, 2022
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    My heat and AC work great, the issue seems to be that the panel doesn’t get enough power most of the time and is dim as a result and won’t let me make selections. Not sure if the issue is internal to the circuit board or simply a power supply issue. Fingers crossed.
     
  5. bjwhite

    bjwhite F1 Rookie
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    You check your hidden fuse?
     
  6. ChoonHound

    ChoonHound Formula 3

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    Why would a fuse cause a brown out situation? Sometimes it works fine, just not for long. Could be once it heats up it or the vibrations of driving makes it fail. It’s not a binary situation.
     
  7. bjwhite

    bjwhite F1 Rookie
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    Because what happens is the fuse holder gets a ton of resistance in it and melts, while the fuse generally stays intact. As this occurs the resistance grows, and could cause power fluctuations to the panel until all power is eventually lost.

    My friend's 348 needs a new hidden fuse holder/fuse and we'll be doing that work here soon.
     
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  8. Ferrarium

    Ferrarium F1 Veteran
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  9. GTO Joe

    GTO Joe Formula 3
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    Feb 15, 2013
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    The electrical plug on the rear of the unit has caused documented problems of not making good contact. The later units are different as a result. I seem to recall it was because the wiring harness is somewhat short. Check that after the fuse review.
     
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  10. Ferrarium

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    Repining it may work as a last resort, I did my MAFs it takes no time to do. That said... often deoxit and cleaning pins and contacts works for many. Also inside the unit there is a chip board sandwich, they go together with pins, those have been identified as a source of intermittent failure as well, cleaning them and reassembly has worked for many cars. I think it's in the DIY section.

    I'd clean them both with deoxit and some scotchbrite and see. I bet it works.
     
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  11. John Glen

    John Glen Formula Junior

    Dec 30, 2009
    494
    Victoria, B.C, Can.
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    John Glen Wesanko
    I have already done all the above and believe there is a fault in controller circuit boards. Just wondering where to send to an experienced shop to diagnose and repair ?
     
  12. lanab

    lanab Formula Junior

    Feb 21, 2016
    510
    Stockholm, Sweden
    I know a dealer that has one HVAC for the 348 in stock NOS, $4200, PM me for more info.
     
  13. Ferrarium

    Ferrarium F1 Veteran
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    I also have one in a box just in case. :)
     
  14. ChoonHound

    ChoonHound Formula 3

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    $4200. Oooo fa.


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  15. ChoonHound

    ChoonHound Formula 3

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    Ahem. Why I question you guys is beyond me.


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  16. Ferrarium

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    Same reason replacing 30 year old relays fixes many issues. :)

    Make sure they use a glass bullet fuse like post #7 above shows on my car.
     
  17. ChoonHound

    ChoonHound Formula 3

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    Gotcha. I’m willing to grow parts at a problem but my mechanic insists on being methodical.
     
  18. bjwhite

    bjwhite F1 Rookie
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    I bet $10 the mechanic got stumped and searched fchat. :)
     
  19. ChoonHound

    ChoonHound Formula 3

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    No, I asked about it specifically.
     
  20. bjwhite

    bjwhite F1 Rookie
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    Ask him where I can send the bill for my diagnostics fee? :)
     
  21. ChoonHound

    ChoonHound Formula 3

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    Ok, but you have to split it with the 300 other people who suggested it.
     
  22. GTO Joe

    GTO Joe Formula 3
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    That fried fuse saved me $3,000 when I purchased my car 10 years ago. :D
     
  23. ChoonHound

    ChoonHound Formula 3

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    Because you negotiated 3k off for broken hvac? Nice.
     
  24. GTO Joe

    GTO Joe Formula 3
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    Yep! :D The previous owner said he checked all the fuses but actually neither of us were aware of the fuse in question at that point. It was only until I got the car home and began a deep dive here on the forum that I was able to find out about it. When I saw that toasted fuse I got a real big smile on my face that only got bigger when I replaced that green 30 amp and the air blew real cold.
     
  25. ChoonHound

    ChoonHound Formula 3

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    Nice! Did you pay BJ his royalty? ;)
     

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