Fusebox repair | Page 2 | FerrariChat

Fusebox repair

Discussion in '456/550/575' started by fatbillybob, Nov 7, 2013.

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  1. Mr. V

    Mr. V Formula 3

    Oct 23, 2004
    1,247
    Portland, Oregon
    Dave Helms at SRI did some major mods to the fusebox in my '95 456GT: it might be worth chatting him up.

    He's an extremely capable mechanic / inventor with an electrical engineering background who focuses on inventing "fixes" for Ferrari problems.
     
  2. fatbillybob

    fatbillybob Two Time F1 World Champ
    Consultant Owner

    Aug 10, 2002
    26,292
    socal
    I know Dave well. I did not know he had a fix. Is this a service he offers or an exchange bassis or did he troubleshoot one or two circuits for you?
     
  3. Genyosai

    Genyosai Formula Junior

    May 28, 2008
    501
    SC
    Full Name:
    Nicholas
    I guess it depends on the circumstances in which you wonder if it'll hold up. In my opinion, I think this is a fine solution, and I intend to take on the challenge. After looking at your solution, I had the idea to take it a little further and maybe hot-glue the wiring in such a way that it's a little more routed/neat/secure. What do you think?

    Yep :) I Tape up whenever I get to go.
     
  4. ferraridriver

    ferraridriver F1 Rookie

    Aug 8, 2002
    4,134
    Bay Area Calif.
    Full Name:
    Dave
    I think that's an excellent idea, should help with any vibration issues.
     
  5. tazandjan

    tazandjan Three Time F1 World Champ
    Lifetime Rossa Owner

    Jul 19, 2008
    37,985
    Clarksville, Tennessee
    Full Name:
    Terry H Phillips
    Dave- Agree. USAF did not allow solder connections because they tended to vibrate and break over time. Of course, an aircraft vibrates quite a bit more than a Ferrari. Sealing them in will probably be a permanent fix, but you want to make sure you have a good joint because getting that stuff off would be a pain.

    Birdman did fuse boxes for the V8s and possibly Vern, too, but those were a different type of fuse box.
     
  6. fatbillybob

    fatbillybob Two Time F1 World Champ
    Consultant Owner

    Aug 10, 2002
    26,292
    socal
    Agreed! It starts out that way and quickly degenerates to a bowl of pasta. The stack of wires and the the cover screwed down actually put mild pressure on the wire bundle. There is not much movement. Ideally I would want mroe space and have wires not touch at all but this is so much better than OEM where foil traces are separated by varnish on the boards which touch and vibrate against each other and I guess short on each other to help create that wonderful personality that is Ferrari.

    I thought about "potting" the thing in epoxy but then what happens when you want to fix a trace? I felt that just the mil-spec wire and good solder joints were such an improvement and the proximity and shortness of most wire making for minimal vibration I just decided to go with it.

    There is no question that a proper fusebox like a birdman is in order but it is not going to be close to OEM.
     
  7. tazandjan

    tazandjan Three Time F1 World Champ
    Lifetime Rossa Owner

    Jul 19, 2008
    37,985
    Clarksville, Tennessee
    Full Name:
    Terry H Phillips
    FBB- I do not think folks are that worried about OEM, especially if the guts are invisible behind an OEM cover. Function is much more important.
     
  8. fatbillybob

    fatbillybob Two Time F1 World Champ
    Consultant Owner

    Aug 10, 2002
    26,292
    socal
    maybe, with an oem fusebox every mechanic knows where everything is supossed to be as listed in the WSM. If you put a custom box behind the cover you need to make sure it is not only labeled but also you make it more unknown to mechanics. You add an unpredicatable wild card in a world where everything is done and fees estimated on book time. Also when the car is sold people get weird if things are not factory.

    it is also possible that the bowl of pasta repair works better than it looks and it is reversible.
     
  9. tazandjan

    tazandjan Three Time F1 World Champ
    Lifetime Rossa Owner

    Jul 19, 2008
    37,985
    Clarksville, Tennessee
    Full Name:
    Terry H Phillips
    FBB- There is always that, but my theory was everything stays in the same location, just with tougher componentry and connections.

    Need to look a Birdman's boxes and see if he rearranged everything or not.
     
  10. fatbillybob

    fatbillybob Two Time F1 World Champ
    Consultant Owner

    Aug 10, 2002
    26,292
    socal
    it is certainly easier to do it all new and robust. There is the added advantage that you can clip off the 10 connectors to the oem box and put on good amp connectors and new fresh crimps and pins to connect to the new box. Anyone who has looked at the wiring for the fans as john has done knows the benefit there.
     
  11. Mr. V

    Mr. V Formula 3

    Oct 23, 2004
    1,247
    Portland, Oregon
    Here is what the final repair order says:

    "Inspect fuse box to verify it is in good working order. Found 3 wires at the cooling fan connections to be completely burned out...Inspect entire electrical system and do the research required to design and build a 456 version of the fuse box repair kit. Install and fit all."
     
  12. Cribbj

    Cribbj Formula 3

    Probably more like vaporised.....

    There's no way the little copper traces that feed these fans on a printed circuit board are going to live the entire life of the car with these fans cycling on/off. Every time one of these fans starts, it pulls 2.5-4 times its full load current momentarily, which stresses EVERYTHING around it in the electrical system (alternator, wiring, relays) and the weakest link is going to give up first. Since each of these fans is rated for about 20-25 amps full load, that's a 60+ amp surge per fan. (I've measured it.)

    The mechanical analogy to this is driving downtown in the city and doing a full throttle, drag race dump of your clutch at every stoplight all day long. How long can a clutch & drivetrain live, driving like that?

    Then to compound matters, when the fan switches off, there's an electrical spike that gets reflected back into the system which gets absorbed/dissipated by all the other loads, none of which are really "suitable" for dissipating spikes, but especially not the sensitive electronics, like all the ECU's, etc.

    I'm not saying these fan circuits are what cause all our electrical spooks, but they certainly don't help the situation.
     
  13. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,329
    Could the entire fan related part be re-routed outside of the circuit board?
     
  14. Cribbj

    Cribbj Formula 3

    Certainly, but it wouldn't be "original" at that point, and some of our purists feel that these cars must be kept original, regardless how poor that original design was in some areas.

    So to really solve the fan current problem, and increase the reliability of the electrical system would probably diminish the value of the car :) Strange logic, eh?

    FBB's approach is probably the best that can be expected under the circumstances if you're trying to maintain originality. But if originality isn't a concern, then the fan circuits really ought to come out of that fuse/relay box.
     
  15. 360modena2003

    360modena2003 Formula 3

    Jul 11, 2009
    2,329
    Where does the fan take it "temp" reading from?

    As long as whatever is done can be "un-done", the purist are happy.

    I am thinking, if possible, to leave everything as it is in the panel, and just disconnect the fans and re-route them to a completely separate relay.
     
  16. fatbillybob

    fatbillybob Two Time F1 World Champ
    Consultant Owner

    Aug 10, 2002
    26,292
    socal

    I completely agree with John. And John has most likely not seen another "To make matters worse" otherwise I am certain he would have mentioned it. The power entering the FB are two large gauge #4 wires. That is all great but those 2 wires neck down onto the board through small wire traces and then power gets taken off that thin wire trace to other wire traces more in series than in parallel. It is like the electricity has been poured out of a 5 gallon bucket into a teacup! Then overflow from the teacup goes to the next teacup (circuit). These 2 big wires do NOT act as a heart with an aorta and smaller arteries coming off and still smaller arteries branching off those. It is a scarey design! All this could be made better with an aftermarket FB.
     
  17. fatbillybob

    fatbillybob Two Time F1 World Champ
    Consultant Owner

    Aug 10, 2002
    26,292
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    #42 fatbillybob, Nov 10, 2013
    Last edited: Nov 10, 2013
    I have seen this on the 550. The connector with the fans on them can actually melt and the pins for the fans look all nasty burnt and sometimes the wire compromised crimped on the pin. Interestingly, the foil trace and inside of the FB look fine. They might however heat other stuff in the FB and kill something. The weak link seems to be the junction of the pin to pin. In the one case I found corrosion on the crimp which I suspect increase resistance then heat increases. Then this crimp connection fails and no fans. You can't see what the foil traces look like unless you disassemble the FB. So Dave probably just wired around it to avoid destroying the box of creating a new failure while disassembling and redrimp new pin to the input side. I am totally guessing.
     
  18. fatbillybob

    fatbillybob Two Time F1 World Champ
    Consultant Owner

    Aug 10, 2002
    26,292
    socal
    Yes! you can totally do this. Infact, what can be done and what I may still do is:
    1- breadbox wire the FB as I have shown
    2- In the process of refreshing the OEM fans crimp connections about 5" upstream of that place a weatherpack connector to disconnect the input fan wires from the FB
    3- Plug the input fan wires into separate dedicated fusebox
    4- Pull power right from the 12+V junction against the firewall in the footwell

    I think this could be an outstanding modification that is reversible in 5 minutes for anyone who wants to go back to OEM. Our Dave from Maranello Skunkworks took a similar "reversible" approach for the few lucky owners who have the switchable MSW steering ECU's.

    I think that the fuel pump circuits can stay in the OEM FB but those are the next biggest source of worry.
     
  19. Mr. V

    Mr. V Formula 3

    Oct 23, 2004
    1,247
    Portland, Oregon
    #44 Mr. V, Nov 10, 2013
    Last edited by a moderator: Sep 7, 2017
    Dave and his family at SRI were absolutely great about sending me e-mails with detailed explanations and photos during all phases of the lenghthy "sorting out" process.

    Here are a couple relevant ones:

    "Fuse box connections giving up. Looks like the worst is the cooling fans at this point.

    Same configuration as the 512TR we finished prototyping ... so we have a permanent fix for this. The fuel pumps and AC circuits are close behind the cooling fans... no better time than now to deal with it.

    We were working on the GCK at the Motronic ECU's when I decided to inspect the fuse box connections. We have predicted this failure on the 456's but.... congratulations ... you are the first with it that we have seen. Time to offer these fuse box kits I guess. "
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  20. Cribbj

    Cribbj Formula 3

    Here's an alternative approach to FBB's that accomplishes the same thing, but where all work is done in the engine bay, and nothing is touched or spliced in the existing fusebox.

    This method will install new power circuits to the fans directly from the battery, and the old power circuits will now be used as control circuits to to activate new, heavier duty relays. By using the old power circuits as control circuits, the amount of current passing through the existing fusebox/relay board will be greatly reduced.

    If done correctly, a higher quality, and more reliable power circuit to the fans will result, and it should not be "too" obtrusive.

    Purchase these items:

    A pair of Cole Hersey 70 amp relays, model RC700112RN. These will be the new relays that will actuate the fans. Purchase mating sockets for them also. (Alternatively you could purchase a pair of 75a Bosch model 0 332 002 150 relays. Both are available from Texas Industrial Electric here: relays continuous duty 12 volt & 24 volt DC power relays,starter relays). Lower amperage relays are available, but due to the inrushes and spikes mentioned previously, IMO, I wouldn't use them.

    A pair of inline glass fuses & fuseholders with pigtails, of the type used for installing car stereos. The inline glass fuses are preferred over the ATC type as they have more surface area to pass the current, and won't overheat & melt. They should have either #12 or #10 pigtails.

    A pair each of Metripack 630 male and female 2 pole connectors of the type used on the fans (ie, 2 x 15363993 with male terminals and 2 x 15363990 with female terminals)

    20' or so of the type wire that FBB is using, but in red, 12 gauge (McMaster's has it), and about 5-10' of the same in black, (length of black will depend on where you'll earth the new relays.

    Various crimp type ring & spade type terminals, heat shrink tubing, etc.


    Installation:

    1. Install the fuses "near" the battery and wire them to the + terminal. I would probably drop down from the positive terminal, and "hide" the fuses in the congested area around the battery bypass switch, CAT ECU, etc. then run the wiring in step 2 through the chase on the fender well with the A/C hoses, etc.

    2. Install the relays near each fan and wire from the fuses to the relays' #30 terminals

    3. Wire from the relays' 87 terminals to the + side of the new female Metripack connectors, so they'll plug into the fans, then unplug the fans from the existing harness and plug them into the new female Metripacks.

    4. Wire from the - side of the Metripack connectors to a suitable earth on the car chassis, or back to the battery itself. Do not use the radiator or any part of the cooling system as an earth!

    5. Wire from the new male Metripack + terminals to the relays' 86 terminals (+ side of coils)

    6. Earth the negative side of the male Metripack and the relays' 85 terminals (negative side of the coils).

    7. Plug the new male Metripacks into the old harness

    8. Test that the fans come on normally
     
  21. fatbillybob

    fatbillybob Two Time F1 World Champ
    Consultant Owner

    Aug 10, 2002
    26,292
    socal
    I think your idea is not as clean as hiding all the non-oem stuff in the passenger footwell. If there is any future trouble shooting there is an extra failure point which could be eliminated fast by my fast replug idea.

    3 reasons your idea is better:
    I like your idea better because first there is less bending and working in the footwell which is painful.
    Second, you are guaranteeing good mil-spec wire + and - to the fans. It is almost like a clean hotwire right to the fans. Fans work better with good clean power and I wonder how much of past overheating issues can be blamed on fan system inefficiency? Heat makes more resistance sapping power. I like your idea especially as a must do for those living in hotter climates.
    Third, I got 2 550's and at first I thought someone was playing a fast one but both my cars are the same way believed to be relatively untouched by human hands. I have not looked at this in a while but my memory is the WSM labels the fans fuses as 30A but both my 550's have 40A in there! An error? Someone at Maranello realized that 30A's were popping? John has it measured at 60A transient? Is there something that happens in an old motor where John would have such a high spike or is this realistic? Either way John's idea would have enough headroom for the spike he is seeing. I'm not sure why that just doesn't blow the 40A fuse but I don't understand electronics. Maybe we could protect the OEM circuit by doing 30A as in the WSM and see if the fans kills those lighter fuses? If the car can work on 30A maybe the simple breadbox rewire inside the FB is ok? What conditions would cause a fan fuse to blow besides a direct short to ground?
     
  22. Cribbj

    Cribbj Formula 3

    Carl, the wiring for these fans is interesting. If you look at the feeder circuit conductors that Ferrari provided, I'm betting they're 1.5mm2, which "might" be good for 15a in a hot engine bay. Then if you look at the wire that SPAL provided on the fans itself, it's at least 4.0mm2, which is good for around 35-40amps. The reason this is interesting is because "normally" the circuit feeding the load has larger wire than the load itself, to account for voltage drop, etc. In this case, it's the inverse, so not only is the fusebox not designed well, but the engine bay wiring isn't either.

    On the inrush current, it's normal for motors to pull 3 to 6 times their full load current when starting. This is because of stiction, magnetic inrush, and some other weird things that only EE's are interested in.

    Different applications have different FLA multipliers, like a simple centrifugal pump application may only pull 3x FLA, but the absolute worst application is, you guessed it, fans and large blowers. They pull up to 6x FLA, and it's because of their high moment of inertia.

    What this means is that fans with big blades don't like to be accelerated or decelerated quickly. It's better for them to be started and kept running than to start/stop all the time - or just the opposite of how we operate these fans in our cars.

    So what would pop a fuse that is larger than the fan's rated current?

    There could be more stiction in an older motor, as a result of crud buildup or a bearing that's dragging, and this will cause it to pull higher than rated current.

    A blocked fan will also pull much higher than FLA - this is called locked rotor amperage or LRA, and it's in the neighborhood of the starting current, and this will pop a fuse almost as fast as a short circuit.

    And believe it or not, fuses become fatigued and can fail over time, especially when the fans are subjected to these multiple starts & stops with their inrushes and spikes.

    Carl, I think you've done a great job with that fusebox rewire, but you/we really need to get the fan circuits off that board and onto their own dedicated circuits. Your way of doing this will work, but it still utilises the undersized Ferrari wiring going out to the fans. Also, I may have misunderstood your approach, but I don't think you've done anything about new relays with your rewire?
     
  23. fatbillybob

    fatbillybob Two Time F1 World Champ
    Consultant Owner

    Aug 10, 2002
    26,292
    socal
    John,

    Thanks for the explanation. I understand and you are correct. I have never looked at the wiring out of the firewall. I only looked at the wire going toward the firewall out of the connectors. On my car there are 2 sets of 2 12 gauge wires crimped together and plug into the FB. One is left fan and one is right fan. I have seen the burn in the pictures above on many fan connectors at this point and just assumed there was some dynamic that caused this to happen because of the design. I assumed that this heavy twin wire traveled all the way to the fans via the engine compartment. If those heavy wires are not there then you are 100% correct you got to have wires big enough for the load for an old tired fan motor. And no I used the OEM relays. Everything I did was stock except the mil-spec wire. It all repackaged nicely and no one would know unless you open the FB cover or got suspicious because everything in my car works.
     
  24. Cribbj

    Cribbj Formula 3

    Carl, that's even more interesting, because 2x12 gauge conductors would be PLENTY for each fan, even using normal automotive hookup wire (Tefzel, etc.) I was looking at the wires at the fan end, and there's no way they're 12 gauge, but are more like 14 gauge, but since that dimension doesn't exist in Europe, I'm thinking they're 1.5mm2. "Possibly" 2.5mm2, but I doubt it.

    Can you confirm those 2 x 12 gauge (probably 2 x 2.5mm2) conductors are definitely for the fans? It would be logical, because they're the biggest loads in the panel. I'm assuming all conductors are "hot"? No negatives?
     
  25. fatbillybob

    fatbillybob Two Time F1 World Champ
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    Aug 10, 2002
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    Geez! My appologies. I got so many projects going I had a total brain fart. I swear it was twin wires but was only single as expected. I just checked both 550's the blue connector closest to the RF tire pin 5 and 6 are the fans. The wire measures on the caliper 3mm including the cladding.
     

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