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AC Not working - think I need a new fuse box

Discussion in 'Boxers/TR/M' started by Loudoun_Prime, Aug 12, 2020.

  1. Loudoun_Prime

    Loudoun_Prime Rookie

    Jul 10, 2020
    10
    Aldie, VA
    Full Name:
    Doug Magee
    Hi - so my AC stopped working and I pulled all the relay and fuses related to AC - all good. I think pulled the plugs and you can see in the picture what I found. What do people recommend for replacing the fuse with a more robust unit? Thanks in advance for any advice :)
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  3. clinton

    clinton Rookie

    Feb 16, 2013
    37
    Houston
    I doubt you need a new fuse box. You should change the clips and those white connectors. Add a relay for the ac power which, I think comes from the bottom right connector. That is where to start.

    Sent from my SM-G950U using Tapatalk
     
  4. Steve Magnusson

    Steve Magnusson F1 World Champ
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    Jan 11, 2001
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    You've got the same 5 burned high current connections that every stock TR eventually suffers from:

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    If you do a search on "white connectors" in this TR forum you'll get a bunch of prior threads. IMO, you have three options:

    1. Rewire things yourself to bypass these connections,
    2. Add remote relays to bypass these connections and their relays (the Dave Helms'/SRI solution), or
    3. Get a fuse-relay panel with thicker traces or discrete wiring that transfers heat away from these connections better (the GT Carparts and/or Guido's solution).
     
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  5. Loudoun_Prime

    Loudoun_Prime Rookie

    Jul 10, 2020
    10
    Aldie, VA
    Full Name:
    Doug Magee
    many thanks - it sounds like number 3 would be the best permanent solution. Any downside to it? Will any of these be an issue for classique certification?
     
  6. EZORED

    EZORED Formula Junior
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    Nov 24, 2007
    605
    Scottsdale, AZ
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    Dennis
    I used Guido's for my 512tr and am very happy. GT did not have a 512 board available at the time. If I had a Testarossa, I would probably use GT. You will need to buy some white connectors also. GT has those also!
     
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  8. Steve Magnusson

    Steve Magnusson F1 World Champ
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    My only reservation about either of the #3 options is not sure that they've have had enough time/mileage usage to be absolutely proved built-proof -- but certainly more reliable than stock. Not an expert on "classiche" (sp?), but #2 is an outwardly visible modification (when the access door is opened) so that may be an issue for that (whereas, I believe, both #3s are well hidden).

    (My own choice was #1, but that's far less plug-n-play.)
     
  9. Grease Donkey

    Grease Donkey Rookie

    Jul 5, 2018
    31
    Zurich, Switzerland
    We're not alone: The melting connector issue is quite common in luxury 80s/90s cars. For example the AC vent connection the no.1 reason why Porsche 928's catch fire .... (ask me how I know:D)

    Here's some guess why:
    As per joule heating https://en.wikipedia.org/wiki/Joule_heating the heat is proportional to the square of the current.
    30+ years old electrictrical components such as fuel pumps, ventilators for engine or AC etc draw significantly more current than they did when they were new. So (at least to some dregee) changing the fuse-relay pannel is curing the symptom not the cause .... :rolleyes:

    Hence another option can be to swap the components:
    - For fuel pumps this is very cheap and easy. I can confirm that this solving the issue on theses connectors.
    - For the engine vents the parts are affordable, but I haven't swapped them yet. I simply cut out a little of the white connector to allow the heat to dissipate.
    - For AC I have no idea. I'm not using it that often....
    (for part numbers see cross reference thread)

    As power equals voltage times current, it's a good idea to make sure that the voltage is OK everywhere by:
    - cleaning/changing fuses and relays
    - cleaning negative ground near the battery
    - cleaning the battery switch in the trunk (that made a huge difference in my car)
    - cleaning any other negative ground (which I have no clue where they are ...)
     
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  10. Clyde Romero

    Clyde Romero Formula Junior

    Sep 6, 2019
    492
    Atlanta Georgia
    Full Name:
    Clarence Romero
    yes he is correct
    your board might be salvaged
    but you must install the relays to keep the high amp draw away from the board
    do this to the radiator fans as well
     
  11. theunissenguido

    theunissenguido Formula 3
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    Jan 21, 2004
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    Micheal Jordan
    3e solution : there are 156 boards installed since 2007 (even 4 x F40) so how much time/mileage do you need to be built-proof ?
     
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  13. Steve Magnusson

    Steve Magnusson F1 World Champ
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    #10 Steve Magnusson, Aug 14, 2020
    Last edited: Aug 14, 2020
    About 30 years and millions of miles driven ;) No disrespect meant -- just have no data at all (before your post). I already mentioned having the larger gauge wire (rather than a thin trace) should be a big benefit for extending the life of the connectors that usually burn up -- but that doesn't mean that you've proved they now last forever (in all atmospheric conditions).

    Can you provide some close-up pictures of how the wires are joined to the various terminals on the backside?
     
  14. Clyde Romero

    Clyde Romero Formula Junior

    Sep 6, 2019
    492
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    Clarence Romero
    Best option is to install relays IMO
     
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  15. Loudoun_Prime

    Loudoun_Prime Rookie

    Jul 10, 2020
    10
    Aldie, VA
    Full Name:
    Doug Magee
    thanks - I’ve decided to go with option #3 - pulled the board and inspected it. Clearly needs to be fixed. Burn thru the board. Yes I spelled Classiche wrong - lol basically I spelled it in Spanish the way it sounds instead of Italian. Hoping it doesn’t take too long to get the board rebuilt as I really want to drive the car right now, but it’s so hot I need that AC working. Appreciate all the advice from everyone!
     
  16. Clyde Romero

    Clyde Romero Formula Junior

    Sep 6, 2019
    492
    Atlanta Georgia
    Full Name:
    Clarence Romero
    I have a spare fuse box from a 512 TR
    PM me if your interested or call me

    clyde
    Or call me
    678 6419932
     
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  17. theunissenguido

    theunissenguido Formula 3
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    Jan 21, 2004
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    Steve, I'm not allowed to put information about those boards in a thread like this. Whas banned already for a month....and a few weeks later my sales add whas closed. Altough I do this as a hobby, F-chat moderator means its to profesional or more a business. Working for a good cause is not appreciated anymore. Will send you a PM with more information.
     
  18. turbo-joe

    turbo-joe F1 Veteran

    Apr 6, 2008
    6,452
    southwest germany
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    romano schwabel
    sad to read such a handling from the mods here.
    so they may overthink their handling and may post clearly rules what is ok and what not. otheriwse there will be much more future conflicts.
     
  19. Mr.Chairman

    Mr.Chairman F1 Rookie

    Mar 21, 2008
    2,936
    New Jersey
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    Robbie
    Send the box out to Dave Helms. I know its a mod but it solves the issue.

    R
     
  20. EZORED

    EZORED Formula Junior
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    Nov 24, 2007
    605
    Scottsdale, AZ
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    Dennis
    I have no experience with the David Helm work around, and if your board is in good condition to start with, it is probably and acceptable solution. Most of these old boards are delaminating and David Helms solution will not correct that. In my opinion the DH solution is at best a temporary fix. You are going to half to pull the board any way, so inspect it and make your decisions. I'm guessing not, looking at the white connectors.

    Also, the DH fix cost considerably more that Guido's new board! It was a no brainer for me.
     
  21. PA32Pilot

    PA32Pilot Formula Junior
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    Mar 5, 2020
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    Jamie Kirk
    Tried to message ya, won’t let me.
     
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  22. campbell360

    campbell360 Karting
    Silver Subscribed

    Oct 15, 2009
    237
    Michiana
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    Doug
    I have an 89 TR where the AC just stopped working too. I would be interested in looking at a circuit board fix. Thanks.
     
  23. Mr.Chairman

    Mr.Chairman F1 Rookie

    Mar 21, 2008
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    Disagree. The longer you wait the more of chance you have to effect the adjacent terminals/connections. The DH fuse box upgrade is rock solid. Going 8 + years strong in my TR which Bradwilliams owns. Probably longer then 8 years. I keep in touch with him and check up on my car making sure its still reliable. Reliable she is. Its a solid fix. Expesnive yes..

    R
     
  24. V4NG0

    V4NG0 Karting
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    Dec 14, 2018
    194
    Looking for parts NLA
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    Vinny
    I actually replaced the Dave Helms fuse box with the GT Parts one, which helped eliminate all kinds of electrical problems that the car was having. Mine could very well be the outlier, based on the support that the DH box generally gets—but it was not rock solid in my car.
     
  25. enzo52

    enzo52 Karting

    Aug 14, 2008
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    Depensadie Seraphin
  26. xplodee

    xplodee Formula 3
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  27. enzo52

    enzo52 Karting

    Aug 14, 2008
    129
    France, Paris
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    Depensadie Seraphin
    Very nice product. ! But it isnt resolving the biggest problem. The female connectors inside the white plugs with the wires. Those connectors are made of cheap metal. And knowing metal is softining with the cycles of heating up and cool down slowly. So in no time those connectors are loosing grip and then we have bad contacts.....burning contacts, wires and white plugs. What you need is brass connectors. Brass gets harder and harder when heating up and coolin g down slowly.
    The one with this solution is the only solution that solves those heat problems.
     
  28. EZORED

    EZORED Formula Junior
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    Nov 24, 2007
    605
    Scottsdale, AZ
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    Dennis
    You may be right, but the originals have lasted 30 + years and I don't think they are brass. So at the worst case scenario, its the next guy that's going to have a problem. Most of us will be pushing up daisies!! LOL
     
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