Repairing 348 climate control | Page 2 | FerrariChat

Repairing 348 climate control

Discussion in 'Technical Q&A' started by RAYMAN, May 28, 2004.

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  1. ernie

    ernie Two Time F1 World Champ
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    Keep in mind, that was rate was from over 8 years ago. ;)
     
  2. john a barnes

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    Maybe it's coincidence, but I just put a new compressor shaft seal in for a slow 134 leak and the next day my C/C panel start blinkin' out. What the----?
     
  3. Qavion

    Qavion F1 World Champ
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    The display or the lights? The large connector is problematic on these cars. There are quite a few posts on this on the 348/355 forum. Try wiggling the connector to see if the problem goes away (or gets worse).
     
  4. john a barnes

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    The display and the lights. So, I get done filling filling the Freon, sight glass says it full and 47deg. at the vents. Next day I re-checked with my sniffer again and still no leak and operation is fine. Hot ,cold ,high and low air. Great! One day later press a/c and all the lights light up, panel then goes dim and the digital stuff shows a strange LED block display. So, last night I took it all apart and put De-Oxy on the contacts. Plugged it in to check and it worked just fine. I Need to do sticky center stack any way so 2 birds with one stone. So this morning (8-4-20) I plugged it in and played with it. Now it seems like something is sucking the power away between hot and colder requests. Fresh air is OK if I don,'t touch temp or fan request. Any ideas? And where are grounds 99, 100 and 101?
     
  5. john a barnes

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    Where is the forum on this whole thing?
     
  6. john a barnes

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    BTW, I did the melted fuse thing Under the Frunk last year.
     
  7. Huskymaniac

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    On using the contact cleaner, are we talking about the connector on the upper PCB or are we talking about the giant yellow connector that the wire harness plugs into? And are we talking stabilant 22A or something else? If we are talking about the connector on the PCB, what did people use to get the cleaner in the small holes? If the answer is, just spray it in there, how did you avoid it not getting everywhere and potentially damaging something?
     
  8. john a barnes

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    Husky, I had to take the Frunk apart again to install a fire extinguisher. The damn fuse and fuse holder was melted again. So I extended the 12 gage wires out to the receiver access cover and put in a new holder and a 40 amp circuit breaker. I zip tied it to the Freon pipe and all good again. And yes, I used De-Oxy-it with the little built in cap brush on every pin inside and back. BTW, De-Oxy is a little cheaper than Stabilant. Check your fuse again also. GL
     
  9. Qavion

    Qavion F1 World Champ
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    Probably busy on the 348/355 forum, John ;)

    The fuse powers heavy duty stuff like the blower fan (with current control by the fan controller) and the compressor clutch as well as all the other stuff. Have you thought about replacing any of these components rather than putting bigger fuses and wires in?

    Miro is working on an updated fan controller here:

    https://www.ferrarichat.com/forum/posts/146969330/
     
  10. john a barnes

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    Quavion, I want to tear it apart and get B+ on a 10ga wire from near the battery and use an HD relay to send it home. The amps are piling up under restriction some where and blowing these fuses. And it may be at the fuse holders. That's why I put an HD circuit breaker for now My battery is up front so it shouldn't be too hard. But it is quite often time consuming on these cars. I need to grab the wiring diagram and do it. Gotta' find the time. It's Wintertime up here and my car is all wrapped up in storage right now. BTW, I think an amp clamp is the next test the way I have it set up. We shall see.
     
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  11. Qavion

    Qavion F1 World Champ
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    +1

    I'm having trouble wrapping my head around this. High amps (currents) are generally produced by low resistances/resistances. e.g motors starting present low resistances (and high currents). The high currents blow the fuses.

    I can't recall if I sent you my diagrams, but here's the one for the HVAC:

    https://www.dropbox.com/t/OyLEJIsdg2A07Gu3

    Link expires in 6 days.
     
  12. Steve Magnusson

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    Melting the fuse holder is caused by I^2*R heating at the connection(s) between the wiring and the fuse (or the wire and its terminal) not the current being too high (if it was too high, the fuse would blow). The unwanted resistance, R, is insignificant for the operation of the circuit (like say .050 Ohms) so about the same basic current flows (and the fuse doesn't blow), but a current of something like 25A going thru just .050 Ohms generates about 30W of heat (so like having an incandescent light bulb inside the connector) = melts the surrounding plastic. And the heating is a positive feedback situation -- if it's got a little resistance, it heats up a lot, which oxidizes and weakens the metal contacts, increasing the resistance, increasing the heating, increasing the oxidation, increasing the resistance, etc. until failure. It's not easy conveying even 10A continuously in a circuit -- when you get up to conveying 20A~30A, it takes really good connections (and big wires).
     
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  13. Qavion

    Qavion F1 World Champ
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    Makes sense. Thanks, Steve.

    Some folks with this HVAC problem are switching to bullet-type fuseholders. I guess there is little or no metal/plastic contact in this case.
     
  14. john a barnes

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    You nailed it Steve. That's why I mentioned a bigger wire setup. I thought about a stereo Amplifier fuse, but I didn't want that goofy look under there. I'll see what happens next summer with my circuit breaker. BTW my eyes are getting old so i assembled all the wiring diagrams in a 4-square arrangement. I was cutting and pasting like a 3rd grader. Now I have an entire portfolio with the legends. Unfortunately they're in the car frunk in storage.
     
  15. Rpin

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    Do you have a contact for this please? Website or email?
     
  16. john a barnes

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    Hey folks, I found the problem besides the fuse in the frunk. It's the #1 pin Morrone wire at the connector on the HVAC control head as pictured here. My full explanation is on the other thread for some reason. It IS the fix. It's not corrosion. It's the female inside the black housing under the yellow cover. No problems for a month now. Yippy. See all on the other thread.
     
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  17. Rpin

    Rpin Karting

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    Where's the picture??
     
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  18. john a barnes

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    Sorry, I didn't take any. I fix cars and trucks for a living. I just diagnose and repair and get on to the next one for 40 years. BUT, I saw pictures on one of these threads that show console disassembly and removal. I'm usually so busy that I don't bother to post anything. But honestly, stop searching for a new HVAC head until you repair this connection!!
     
  19. steved033

    steved033 F1 Veteran
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    ...but in #41 you said "as pictured here"

    meaning in the thread?

    sjd
     
  20. john a barnes

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    Sorry Steve -I thought it was this thread with the pictures. It's on this Chat in one of these threads!!! haha
     
  21. john a barnes

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    Steve, I just looked again. There are 2- 348 climate control threads. Fire up your computer and find the one that starts with RAYMAN -banned. Whatever that means. Take a look at the giallo wire connector with the black clip on top. That gets removed to get to the heart of it all. I don't know how to re-post onto that thread. Spread the word.
     

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