Project SC300 Road Racer: Part 12 – Cabin Fever


The big circular milspec going into the firewall is a pretty busy connector.

The front firewall main harness connection is a circular milspec MS 3470 18-32P. This is a 32-pin connector, and we’re using all but 5 of the connections. In hindsight we should have used a 32-socket connector, as this provides for some safety (as pointed out in the comments on earlier threads). It’s theoretically possible for something to get into the pins on the other side of this connector when it’s disconnected. A socketed-connector would make that harder. But, live and learn.


We opted not to fill this particular harness leg.

With 26 wires in this leg, we would have needed quite a lot of filler wire. It’s also a somewhat long leg, which means using a lot of expensive wire, and taking a lot of time to do it. So, we opted to take the easy way out. However, notice that we properly alternated the lay of the cabling here, and made sure to lace in the opposite direction of the outermost cable lay.


Here’s a mess of harness legs, that all need to end up in more or less the same place – the Racepak Smartwire.

The cabin is a mess of wires and legs going to all different places, but eventually they more or less all come together into the Racepak.


Zip ties can temporarily hold our legs together so that we can begin to concentric twist everything.

As none of these wires are carrying signal, we don’t have to worry too much about which wire gets wrapped around what or in what order. But we do need to wrap them all up correctly.


After a lot of time and cussing, we have a mondo multi-legged harness, with lots of Dymo labels!

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