NB have a separate harness, for engine controls at least. NB1 and NB2 don't differ that much (except ignition).

Just to make the "truth" even less obvious.


When I swap engines back and forth, the OEM harness is not that bad, but all-in-one contact at the FW would not hurt (with provisions for all the small extra stuff). The OEM connectors are not designed for that many connect/disconnects.

You can make a venn diagram for racers and experts. not all racers are experts, not all experts are racers.

You would be amazed how many "pro race engineers" don't have a clue, and refuse to listen to reason because they are a "professional racing engineer". before you listen to anyone in the paddock make sure they run at the front, or built the car that does.

Im using a microsquirt module and its 8' harness in my project, not complete.
Very basic, but more than capable.

Other things like defrost, wipers, and lights will be wired through push to reset fuses and any associated relays (starter)


If your starting from scratch, you REALLY don't need to over complicate things.


What ECU are you running? That will have the biggest impact on how you wire it.

Third time I've typed this now.

I'm in the process of building one, slowly, probably one circuit at a time. There are a couple reasons for this. First is to learn how to do it; I'd like to build a purpose built at some point. Second, two of the previous owners made some interesting wiring decisions that leave me concerned about reliability (including one who has posted here about how you don't need to do it). Third, I spent about half an hour after a track day trying to figure out why my tail lights didn't work. I'm 6'5" tall. The less time I have to spend looking at breaker panels in the footwell the happier I am.

So far I've only installed the data system, which meant fabricating a bunch of custom cables. One side had AIM's crappy, soldered, non motorsport connectors. The other DTM connectors. The AIM stuff took way longer, cost substantially more and was a way bigger pain. The DTM stuff was cost effective, easy, robust, and a pleasure to use. I know which way I want to go in the future.

I've taken a few cost cutting measures. I'm only using one color wire. It'll take a little longer to ring stuff out in the future, but I can live with that. I'm also not using expensive heat shrink. I'm using normal stuff for long runs, with marine grade adhesive backed stuff at either end. It works for the car's purpose and is available at Harbor Freight. Under the hood will be DR-25. Breakers and switches are replacing the fancy PDM systems. Maybe not as nice, but plenty of top level cars used them for a long time.

All together I have about $25 in wire, $60 or so into a nice set of used DMC crimping tools, maybe $30 in DTM connectors, and maybe $15 into heat shrink and something like $10 for switch and breaker. No it's nowhere near an entire car, but I suspect I'll only be in the $1000 range unless I go crazy with AutoSport connectors instead of MilSpec stuff.

If you're in Northern California I can even help you out with tools.

Oh and Ballenger Motorsports (post here as vtjBallEng) and ProWire USA can get you most of what you need. Digikey is good for switches and breakers.

Aircraft spruce and dell city are also options when looking for switches realys and breakers. But I have to say, for individual relays the delphi/packard relay kits that B motorsports sells are clean as fuck compared to the relay kits from dell city.

This is what we took out of Bruce's stock wiring harness. It represents painstakingly identifying each wire, confirming the color code, checking continuity and then physically unwrapping the shrouding and pulling it out.

Over and over and over...

I just did the same thing to the mx6. Sucked. I could have built a new harness faster.

Rywire told me no thanks awhile ago.

Plus goddamn 1. :bigtu: