Adding more circuits to power accessories

Our Cougars came with a barely adequate fuse box. If you want to add accessories like an electric fuel pump, EFI or even a better sound system,you really need to add additional fused circuits.

A few years back I helped develop a modular fuse block system that was actually intended for boat manufacturers. The way it works is that each module can hold a fuse or a solid jumper. The modules interlock with a link feature so if you need four circuits you just link four modules together. Additional links can make one input serve multiple outputs. These were done before COVID and never really got the marketing effort they deserve.

Here are some pictures to give you and idea about how these work. The blue and purple feet go into keyed slots on the side of the module. You an add more modules to build up as many circuits as needed. Jumpers (shown in black) then interconnect the adjacent modules if needed. Fuses are pictured in green.

Here are some examples. You can run multiple inputs: so you can have new circuits that area always hot and then add more circuits that would only be hot with the key on, and so forth.

Or you may just need a distribution block. If you substitute the jumper for a fuse you can do that.

If you want to run a bunch of circuits you may need to run a bigger wire to power them all. This hows a 4 gauge wire feeding a bank of circuits.

This is with the covers in place

I was looking for something like this a few months ago when I added a carb with electric choke, but needed a relay with switched power as well. I found this Painless setup p/n 70203 with switched and constant power, but found it was too large and didn’t like the look when installed. I went ahead with a single relay for now.

Would be nice to find something small with switched and constant power with a clean look.

Each module is about $3.50 so a lot less money. It would be easy to feed these from relays.

Midlife likey! Very much likey! :think: :dance: :beerchug:

I wonder if you can made a gang of relays similar to the power accessory gang.

Cool idea for sure, lots of options like this in the market but what sets this apart is being able to customize to fit your needs. Being able to add and remove sections is very neat! And no need for particular terminals to assemble making it easy for anyone to add.

I’m going to have to look into those since I would like to run EFI, Electric Fans and Water Pump.

Excellent post, thanks Bill! I’m bookmarking it.


If Bill doesn’t mind I can link a few options for adding circuits I’ve used in the past and what I’m currently planning on using.

Please do add them!

How many amps is it rated for.

40 amps max. 100 amps per block (using 1 input and multiple outputs).

Here are a couple of options Im either using or have used in the past.

First is a complete Relay and Fuse panel. It has two B+ input buss connections that will allow you to wire constant B+ and switched B+ if needed. It houses both the relay and fuses so its pretty easy to keep everything in one place. Its not a kit so you will need to buy the terminal pins and weather seals separately. It uses the Metri-pack 280 series terminals. I like this method as you can built it to suit your needs. I prefer to use Waytek Wire for alot of my wiring stuff but if your not sure what your after it can be daunting. They have everything to build OEM quality circuits and connections. I suggest getting a paper catalog as its easier to sort through and find what you need. I will link terminals Im using so its easier to put together.

fuse panel
mounting brackets
terminal plug seals for unused circuits
14-16GA terminals
18-16GA terminals
14-12GA terminals
20-22Ga terminals
You will need weather seals as well corresponding to wiring GA
Micro Relays used
Mini fuses used. (choose your amperage)

If your going this route I would suggest a good part of crimpers. They are not cheap but worth it when when working with stuff like this. They supply the proper tight crimp needed. These have worked well for me

If putting this together is not your style there are premade versions out there. I believe mfc133 used one of these for his EFI and electric fan installs.

Another option I have used before was this. I only needed fuses and ground circuits and not switched B+ I did have to mount the relays separately which can add to the under hood challenge. I prefer to be as simplistic and clean as possible when it comes to wiring.

I built my own panel using nutzerts to mount the fuse panel for a low profile mounting solution.

This option is much easier to work with is that all it requires is ring terminals to build your circuits. This particular module includes a B+ and B- ground buss bar so everything can be situated in the the same place. The down side to this option is its obviously not water proof. I believe there may be smaller versions of this as well but If Im not mistaken you do not get the ground buss bar.

While we are on the subject I link some of my favorite wiring coverings.

When more heat protection is desired, be mindful its not as flexible as the above. It works great on battery cables running by the exhaust or headers.

Found another option with a small footprint. Waterproof and prewired with one constant and three switched circuits. I wonder about the reliability of those micro relays though…I’m not familiar with them (Song Chuan).

How do I get my hands on some of these?
Is there a website?


Very clever design! If I were adding power accessories, that is exactly what I would be looking for!

Dont forget relays. I had them for both headlight doors , hi and low beam ,ac compressor , both cooling fans along with all the factory 67 relays
Reduces load on hl switch and ac controls

I was surprised that these didn’t really get much interest so I sort of shelved the idea. I do have some if any one is interested $3.50 each plus shipping. A small box of these, say 10 or so would cost less than $5 to mail. Message me for an exact amount.