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A previous owner performed the much needed headlight relay upgrade which places two relays on the firewall on the left side of the engine compartment along with a large mess of wires and inline fuses. Now I'm adding an electric fan conversion to the mix, which adds another relay and fuse. Modern cars use relay boxes to keep things tidy and make relay and fuse replacement a breeze, so why not our spiders?

The box is under development, I have started CAD design and produced a prototype. Some pictures are attached of current stage of development. Final version will be smooth black finish. Dream with me here - it fits perfectly in this spot of the engine compartment almost as if Alfa anticipated this evolution a mere 42 years after production of my '78 car. In my car the oil vapor separator was relocated to the other side of the car so the mounting post is available to mount the relay box. I don't have an external voltage regulator so I can secure the box to the posts left there as well.
 

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Discussion Starter #3
Yep, makes prototyping a breeze. Plug and play is possible, but I would need reference on wiring in that area in the stock wiring harness. The previous owner installed the headlight relays, no idea what it looks like without. Simple male pin connector compatible with the headlight might do the trick, but you'd have a long stretch of wire left from the stock harness. The engineer brain sees this as wasteful voltage drop. My plan is to cut existing headlight wiring and install with 1/4" fastons. Then provide B+ directly from the alternator and ground to nearest ground lug or to chassis.
 

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Could be a nice solution for many people but probably not me as I have 5 extra relays under the hood = Hi beam, Lo beam, fan, starter and ignition. Ignition may surprise some people but I had a significant voltage drop at the coil when it was on the same circuit as the other stuff that is on the ignition switch circuit.
 

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Could be a nice solution for many people but probably not me as I have 5 extra relays under the hood = Hi beam, Lo beam, fan, starter and ignition. Ignition may surprise some people but I had a significant voltage drop at the coil when it was on the same circuit as the other stuff that is on the ignition switch circuit.
Below are some images of a relay box that I installed in a GTV.

In the first image, It is the black rectangle to the left of the clutch fluid reservoir. It was store-bought and cost circa $19 in 2016. I made a small standoff from Delrin and rewired all the circuits.

I installed relays for the high beams and low beams, replaced the factory-installed one for fog lamps, and installed a relay for the aftermarket SPAL radiator fan. There are relays for the starter and the ignition in a box on the steering wheel column inside the cabin. This under the hood box does have room for the starter and ignition relays but I installed those relays about 5 years before I installed this one and I didn't have a strong desire to make another wiring harness.

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Discussion Starter #6
Hooo boy, that's a beaut. If only I had found one like that - everything I found was above $150 and much larger....
 

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Below are some images of a relay box that I installed in a GTV. It was store-bought and cost circa $19 in 2016.
So it appears that nunki bought a 6 relay/fuse box for $19, while stevespiderguy is 3D printing a 4 relay/fuse version. I understand that stevespiderguy's version will be more compact, but just getting one off-the-shelf for $19 has a certain appeal.

nunki: Do you recall where you got that box?
 

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That is quite compelling, as mine will cost a fair bit more than that. However, I don't like cramped wiring and those boxes look like they are less elegant to install (requiring wires to be cut to exact sizes) so I will continue development of my more flexible solution. The images do inspire alteration of my design to be more compact. I see in those boxes they allow for less space around the relays to grab and remove them. In addition the relays do not have pull-out tabs so the box can be a good inch shorter.

@nunki how do you remove the relays without space around them to grab them? Do you need to use a puller?
 

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That is quite compelling, as mine will cost a fair bit more than that. However, I don't like cramped wiring and those boxes look like they are less elegant to install (requiring wires to be cut to exact sizes) so I will continue development of my more flexible solution. The images do inspire alteration of my design to be more compact. I see in those boxes they allow for less space around the relays to grab and remove them. In addition the relays do not have pull-out tabs so the box can be a good inch shorter.

@nunki how do you remove the relays without space around them to grab them? Do you need to use a puller?
I bought the relay box that I show in my post from this company. It came with clear instructions. Over the last five years, I've bought and installed 6 of their relay boxes. Two in Alfas and four in trucks. I've directed other mechanics to this company and was told by them that the company bends over backward to be helpful.

Not sure what you mean about grabbing the relays. I've never had a problem.

Steve, I have designed and had fabricated dozens of 3D printed parts for cars but when I have an automotive problem I usually start with the premise that I'm not the first one to have encountered this. In my case with this Alfa, it was how to added needed 5 pin relays to circuits that didn't already have them? I actually created a model of what I wanted the box to look like in Solidworks. Then I went looking for it on the Internet. And I found one that suited my needs. On to the next problem.
 

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Every possible combination of relay and fuse box are available as close as your nearest auto salvage yard. Quite reasonably priced.
 

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Not sure what you mean about grabbing the relays. I've never had a problem.

Steve, I have designed and had fabricated dozens of 3D printed parts for cars but when I have an automotive problem I usually start with the premise that I'm not the first one to have encountered this. In my case with this Alfa, it was how to added needed 5 pin relays to circuits that didn't already have them? I actually created a model of what I wanted the box to look like in Solidworks. Then I went looking for it on the Internet. And I found one that suited my needs. On to the next problem.
I've always found relays difficult to pull out of their sockets due to limited space around them so I have designed for greater clearance than these boxes usually have. Maybe this means I'm old. I'm particular and any existing solution doesn't seem to address the problem exactly how I want it to be done. Maybe this means I'm both old and an engineer.
 

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Ignition may surprise some people but I had a significant voltage drop at the coil when it was on the same circuit as the other stuff that is on the ignition switch circuit.
This ignition relay is probably the cheapest performance improvement you ever made.

Nunki, I picked up the same fuse box on Amazon to install in a Lotus Elan I had. It is a nice size, just enough for the extra circuitry I wanted to add. Like relays for the headlamps. Tried to put some sanity in the British electrics with Chinese hardware.
 

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I'm building a harness from scratch for my 912 and decided to try weatherpack terminals mini fuses and micro relays. It is pretty impressive how small this thing is and the terminals are more reliable than fastons.

 
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