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Discussion in '456/550/575' started by fatbillybob, Nov 7, 2013.
Great, so what would be the best "source" for temp reading for the fans?
Depends on whether you plan to use the OEM strategy for turning them on/off, or not. Ferrari used a strategy where the A/C ECU is supposed to activate the fan(s) if a certain head pressure is exceeded, or the temperature of the coolant rises above a point. If this doesn't happen, then a 2nd temperature sender connected to the main Motronics ECU is supposed to take over and turn the fans on.
Carl's method described below bypasses the existing fuse/relay box, but it also bypasses the above strategy and I don't think he's allowed for new relays or how to actuate them.
You can put temperature switches or senders nearly anywhere in the system, but you'll have to take into account the point where you're sensing, and how high the temperature can go before activating the fans.
I like to sense where the coolant is the hottest, same as Ferrari did, so the sensor would be in the rear water collector manifold, under the intake manifold.
I don't think so. I have not studied the system. I look at it as very crude. Basically I see red 4G hot wires going into FB. There is relay switching in the FB to route power out the blue connector pin 5 and 6 as wire disappears into the firewall on the way to both fans. My method keeps everything Ferrari intact and does the same thing you propose except keeping the new heavy duty fuses in the footwell and using the OEM wire to the fans.
However, the reason I like your way better is because your method would use new good mil-spec wire to the fans with plenty of headroom for aging fan demands. Relays would be more exposed to the elements (heat,dirt,water) in the engine bay. Is that bad for relay life? I have no clue if it matters. Perhaps they can be boxed well. We don't have problems with engine based relays in GM cars but are the under hood temps as hot? The 550 can make crispy critters out of an OEM fuel injection harness.
Carl, perhaps I misunderstood what you're doing; correct me if this isn't right:
1. You're cutting the wires "leaving" the fuse/relay box going out to the fans
2. You're putting a new fusebox in the footwell that takes power from the +12 stud, and you're feeding "new" power from this fusebox to the cut wires going out to the fans.
If the above is correct, then you've bypassed the existing relays, and the OEM on/off control strategy, and you're feeding a constant +12 out to the fans, and they'll run all the time.
Here's a schematic of how the control circuit works; it's actually a pretty elegant little scheme, and you would need to figure out how to duplicate the functions of relays 5, 6 & 7, and bring their control (coil) signals out to activate them.
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I know it's stating the obvious, but why not use the + on M1 and M2 to activate new relays. Sort of like I did on my auxiliary fans? IOW, trigger terminal 86 with the original fan wires?
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Mark, that's exactly what I described in post 45
That is indeed what you said.....Sorry....
Mark, no need to be sorry; you explained it very well, in far fewer words than I did, and people will probably understand your explanation a lot better
Conciseness in the written word is something I lack.
Nope I'm doing the same thing as you or mark described using the M1 M2 wires. Those wires on the fans go from fans back through firewall to FB. I'm starting after the FB and on the passenger side of the firewall. That's all we are on the same page. But your method going to the fans and running mil-spec wire for the fan power using the old fan power to trigger the new mil-spec wires is a better way to go because the Ferrari wires suck. I'm sure we confused everyone by now. For those with scrambled brains just ignore this banter and go with John's post 45.
Has anyone measured the voltage at the fans, i.e. at the connectors closest to them?
It would be interesting to compare this to the voltage at the battery, to get an idea of the voltage drop induced by the relays, fuses, long wires...
I also had a problem with the instrument lights, and it was not the fuse nor the relay.
The garage I usually bring my M550 declared that the fusebox needed replacing, since that is where the problem usually sits, and there is no way to properly analyse the reason and fix it, so replacement was the only alternative offered (for about 2.5k USD).
Fine, I tought, after all I am an electrical engineer, so lets have a look at it first.
I admit that that fuseboxes wiring was really weird: 2 double sided, very thin prints with an insulating layer between, connecting all contacts of the fusebox. As far is I could tell, there were no active components the prints, the prints just served to connect 3 types of contacts: The contacts for the connectors, for the fuses and for the relays.
The solder joints for the connectors and fuses looked OK to me, so I left them in peace.
However, the relays had some solder joints that looked like "cold solderjoints" (that is how we call them in german), looking dull and as if the the contact was not properly joined with solder.
So I took all relays out to prevent the heat finto rom going into the relay contacts and I resoldered all relay contacts. Some of those, the ones contacting a large surface copper trace, proved a bit hard to resolder.They need decent heating from both sides (10 seconds or more) until both contact AND sheet copper of the print were hot enough for the tin to melt all around. You will know what I mean if you come across one of those, probably about half of the contacts. After reassembling everything: Bingo, instrument lights worked again !
The resoldering made the the print look a bit burned here and there around the contacts, but there was still enough insulating materlal and the electrons dont care about the looks.
All in all, it was not really difficult. To get the fusebox out is easy (the connectors have a locking mechanism that you will need to press while trying to get the connectors out).
2.5k saved in a matter of maybe 3 hours is not bad...
Hope this hint helps someone else too...
Update: It has been about 4 years since doing this beta test. My spaghetti fusebox repair is still working flawlessly. Everything is still factory connected. I think this summer I will do as John suggests and move the high load items like cooling fans off the fusebox. There is a company I learn of today who is doing this exact repair. Someone is seeing value in going this direction. http://redbaycars.com/remanufactured.html
Will be amazing if they have this for 550s. Didn't see the 550 on their list of boards.
If they don't do 550s, care to do another one 😀
Looking information about 456GT fuseboards....can someone make a picture from the plastic layer on the backside.
Seems that first models 456GT have old model fuseboard like F40, TR, testarossa and 512 old model board.
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Later models 456GT can have fuseboards like 456M, 550 and 512TR
I need a picture of the backside of the older model like the picture above. I want to compare if a 456GT board has the same internal diagram is for one of the others mentioned boards or has its own diagram.
PS: like mentioned in an other reply above, there is indeed Redbaycars.be that sells NEW boards. Those boards are made by me and when I'm out of the country, Stefan from Redbaycars is taking care of the sales department. More information here : http://redbaycars.com/remanufactured/ferrari parts.html
There are already 97 boards installed to great satisfaction of the Ferrari Owners.
This is how the 550 board looks like...there is no modification needed, just plug and play !
I have those new model boards for 456M, 550 and 512 new model.[/ATTACH]