Ferrari 412 Radiator Fans Fuse Melting

Good day Jared,

I can understand the desire for originality, etc. However, the wire that Ferrari used was marginal at best and so it can be highly problematic on higher current loads in terms of its temperature rise, but also the voltage drop across the wiring run as well. That said, installing remote relays and superior wiring to a more direct +12V source (should be fused) will pay tremendous dividends plus minimize future problems and ferrari wiring issues. Using remote relays, etc can be done quite tastefully and/or hidden and so to the result looks totally OEM.
I am very much a stickler for originality, but... where warranted I have no issues to non permanently modify wiring and circuits to improve things, increase reliability, and reduce issues/risks with what was originally done.

Cheers,

Sam

 

funny since acquiring my 400 a month ago I must have read that thread 4 or 5 times already! thank you
So if you found the Lucas to have between 1.1 and 1.5A depending on timing, and you say they are power hungry, but the Spal fans I'm finding on Amazon run 5-8 amps - sounds like although more efficient the Spals are more power hungry, and thus require the separate relays/fuses?

 

Typically I could not agree with you more. In fact in previous posts on the 456 threads I've made similar anecdotal arguments, especially when it comes to 'important' items or systems on older cars. My thought is that if 'this classic' (pick a classic car) were manufactured today they would put 'this' updated newer tech on the car. Radiator/cooling systems, suspension components/shocks, audio (to some degree) just to name a few.
Plus.. for what's it's worth even if I switch to the Spals (or similar) with updated/upgraded wiring/fuses/relays I do still have the original equipment in a box on the shelf to remain with the car for nostalgic purposes
thank you

 

This was under no load. Once you put the fan on the rotor that's another ampdraw. I've installed some deTomaso shrouds, this makes the original Lucas much more efficients (but a tight fit).

 

The spal are ugly, and even more the slim ones with curved blades. At least you should use spal fans with straight blades that are somehow more classic (and deliver more airflow, but are noisier).

The fans from the golf cab (gen1) are a direct fit, blades look ok"ish", and are real power monster if you take the 2 speed variants meant for cars with AC (power >300W !!!)

 

So i’m fairly certain I will not have any issue installing new relays and new improved cooling fans but to the group, a general question about the wiring: is it wrong to simply use the positive and the negative of the original fan wiring to activate the relays (85 + 86) which will go to the new fans? Of course, the power from the battery (30) will be fused appropriately and the other end (87) will go to the fans. One relay for each fan, each with its own fuse. And of course, the fans will be grounded.
If any electrical engineers or owners that have done this before, have any opinions, I would be grateful. Thanks.

 

On a 412 does not mater as it does not have ammeter. Still the best positive source is the positive post of the top alternator, this post is bolted on the left fender.

 

Jaren and 360
I added relays as you propose to my '84 400i. I use power supply from battery to a new NAPA 4-fuse block behind the battery, underneath the wiper motor. I had one fuse for each fan. I mounted Hella light relays near each fan. For the two push fans I removed the front grill and mounted relays very close to the fans and for the pull fan I mounted it on left side of engine bay under the air flow to air cleaner and/or fresh air duct. I used heavier gage wires, and they are pretty well hidden. I spliced the original power wire to the fan and connected to the relay switch contact. The new power wire to the supply of relay and added a ground to the same place the fans are grounded. The spliced wire to the fan is the original wire connected to the power out of the relay.
This has worked for several years.
Ken

 

Just send a picture of the connector. On the Lucas fans, the connectors are "bullets", I suspect the ASTI are using FASTIN-FASTON.

 

Those are the Fastin / Faston connectors.

Cheers

Esben

 

I ended up adding relays for my two push rad fans on my 400. Lots of creative ways to do it. Just make sure you fuse the battery power in to number 30 on the relay. I used 10 gauge wire with an in-line fuse (from battery to relay). I also removed my lower valance and grill and tucked the relays behind the front bumper.
Kind of odd that they’re melting but obviously there must be something causing an increase amperage flow. Either the fans are getting stuck or could just be ‘wiring going bad’.
Cheers

 

TE Connectivity, AMP FASTIN-FASTON 2 Way Nylon, reference 180907-0

RS would be the go-to supplier for many of us, but given your location, you should give a try to 3wayComponents. https://www.3waycomponents.co.uk/product/2-way-6-3mm-fastin-faston-250-series-kit/ . You can try their eBay store for smaller quantities.

 

The fuse-board of the 412 is Ferrari's at its worst...

If I were in your shoes I would beef-up the electric track of the board. See what these user did:

• Clean approach : https://www.ferrarichat.com/forum/posts/137774457/
• A bit more intrusive : https://www.ferrarichat.com/forum/posts/139198884/
• As a last resort (efficient & ugly) : https://www.ferrarichat.com/forum/posts/143643988/
  
• No compromise : https://web.archive.org/web/20210803004938/http://ferrariaustralia.com/Technical/fuse_panel_repairs.htm

You should use silver conductive grease on every single connection (the relay tabs, the fuse tabs, etc...)

 

Once you start removing relays, fuses and the wire looms on those boards, things are getting worse. Solder points brake easily and heat up building is the result. So, the plastic layers are melting, copper connections get fused together and you have a major disaster. All those boards from the 80', 90' and 2000 have the same build-up. F40, 288GTO, all mondials, 328, 400i, 412, TR, testarossa, 456, 550 and 512TR have all the same problems.

 

I've tried to fix such a board for a Renault Speedometer. "Doable", but what a pain: had to reglue the tracks on the plastic layer, add a few blob of solder here and there, watch another part crack while I was fixing the other side! At the end of the day, it works, but if it were not for the soft requirement (the board has to go through several curves), milling a PCB would have made much more sense.

If it was wrong for a Renault speedo, It's just puzzling that someone thought this would make it do with Ferrari high amps anciliaries...