Fuse Box Help from Guido or Other Elect. Experts | FerrariChat

Fuse Box Help from Guido or Other Elect. Experts

Discussion in 'Mondial' started by 85QVEuro, Aug 8, 2022.

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  1. 85QVEuro

    85QVEuro Formula Junior

    Jan 15, 2021
    550
    NYC
    Full Name:
    Joe
    I am at the point in the restoration of my 85 QV Euro where I am cleaning up the fuse box and all electrical connectors. For the most part, things look really good and I have Bosch replacements for all 18 of the relays and all of the fuses. All of the large white connectors to the fuse box look great with no burning but the sole connector on the right (passenger) side of the fuse box has two suspect wires.

    The first issue is in the brown wire in that connector (pic 1). As you'll see, someone tapped into that wire and ran a black wire to the back of the fuse box (pic 2).

    The second issue is in the green wire where someone tapped into that wire and ran a black wire to a yellow wire on a connector in the car (pic 3).

    I can read wiring diagrams but haven't been able to figure out whether I should clean up these connections and re-do them as they were or if I should eliminate these two added wires. Any help would be greatly appreciated. Thanks - Joe

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  2. theunissenguido

    theunissenguido F1 Rookie
    Owner Silver Subscribed

    Jan 21, 2004
    2,674
    Argent/Brasil
    Full Name:
    Guido
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    The middle relay t = upper connector 30 normaly is connected to the lower pin of fuse 21 ; Upper pin of that fuse 21 is getting direct + current from 1 of the 2 big connectors on fuse board ;
    - lower connector 87 normaly is connected to pin 8 (counting from above) of W plug.
    The left relay v = upper connector 30 normaly gets + direct current from 1 of the big connectors on fuseboard.
    Why the transformations are done like this ...?!
     
  3. 85QVEuro

    85QVEuro Formula Junior

    Jan 15, 2021
    550
    NYC
    Full Name:
    Joe
    Guido - First, thank you. Second, I didn't do it :eek:. Third, what do you recommend? Re-wire as they had it (but more cleanly)? Or do something else??
     
  4. theunissenguido

    theunissenguido F1 Rookie
    Owner Silver Subscribed

    Jan 21, 2004
    2,674
    Argent/Brasil
    Full Name:
    Guido
    I see that on the wiring diagram Steve posted, relais have other letters. I would test first if there is direct contact between fuse 21 and upper connector 30 of middle relais. With a multi-tester and the 2 big connectors removed from your board. Then test if you have direct contact between upper connector 30 of the left relais and 1 of the big + connectors on your board. If so, you can cut the white wire.
    Check if there is direct contact between lower connector middle relais and pin 8...
    You should cut the black wires and isolate the rest with tape or so.
    If there are problems afterwards, you know its related to those connections and we will find a solution for that.
    PS = when I say upper or lower connector of the relais, meaning when fuseboard is in normal horizontal position.
     
  5. 85QVEuro

    85QVEuro Formula Junior

    Jan 15, 2021
    550
    NYC
    Full Name:
    Joe
    Thanks, this is starting to make sense. My fuse box is out of the car as I had the front harness out while the car was getting painted. When you refer to the middle relay, and left relay, how are you identifying those relays? I have previously been relying on the diagram below for the relays but now I am going to double check the accuracy of that with the OM that Steve just sent me...
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  6. 85QVEuro

    85QVEuro Formula Junior

    Jan 15, 2021
    550
    NYC
    Full Name:
    Joe
    #6 85QVEuro, Aug 15, 2022
    Last edited: Aug 15, 2022
    Hi Guido - I have the fuse box with me now and did the tests with the multi-meter that you outline above. I have listed your tests as #1-3 below and put the responses in bold:

    1) I would test first if there is direct contact between fuse 21 and upper connector 30 of middle relais - There is direct contact between fuse 21 (labeled A16 Fuel Pump) and upper connector 30 of middle relais

    2) Then test if you have direct contact between upper connector 30 of the left relais and 1 of the big + connectors on your board - There is direct contact between upper connector 30 of the left relais and the big + connectors on my board (the left one)

    3) Check if there is direct contact between lower connector middle relais and pin 8 - There is direct contact between lower connector middle relais and pin 7 in the W connector (counting the pins from the top)

    As you'll see in the photo below of the front of the fuse box, the fuse was missing from fuse 20 (labeled A16 Fuel Pump) and the bottom of the fuse holder is very slightly melted. Please let me know what you think and if it will be OK to cut the short white wire on the back of the fuse box and the black wire on the back of the fuse box and repair the wires on the W connector and basically return it to stock or if I should try some other tests. Thanks for sharing your knowledge - Joe

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  7. 85QVEuro

    85QVEuro Formula Junior

    Jan 15, 2021
    550
    NYC
    Full Name:
    Joe
    Mistake - Fuse 20 should have been Fuse 21 in this sentence: As you'll see in the photo below of the front of the fuse box, the fuse was missing from fuse 20 (labeled A16 Fuel Pump) and the bottom of the fuse holder is very slightly melted.
     

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