1973 240z Custom Wiring From Scratch

[SteveJ]

Make sure the kill switch is rated for at least 40A DC. You don't want to burn it up and catch anything on fire or kill the car while you're driving.

By the way, I bought these crimpers recently: https://www.amazon.com/dp/B0978S514B

I haven't tried them, but they should be able to crimp the open barrel terminals with one shot as opposed to having to hit the terminal twice.

[SteveJ]

Also, I think your revised logic for the voltmeter is a better way to go.

As for reusing connectors, that's what I plan to do in the future. I have a 73 engine harness that isn't in great condition, but the colored connectors are good.

[Matthew Abate]

Here we go!

Nearly 2,000 feet of wire (a surprisingly large number for such a simple and small car), connectors, tape, and the various tools that I didn’t already have for assembling the various wiring harnesses.

The wire is the marine grade from Sherco Auto and Marine Supply that @SteveJ referenced at the beginning of this thread. They did a good job with the order, but I’m a little bummed about the inconsistency of the wire color, in particularly the tracer stripes. I also did not take into account the increased outer dimensions of marine grade wire. The gauge is the same, but the insulation is pretty thick. I might run into some issues when I try to lace the looms through some openings or around corners.

We shall see… 🤞🏻

The connectors are the Vintage Connectors 240z kit. I will let you know how accurate it is to a 1973 setup. There will be obvious differences where the three main harnesses meet due to the lack of the colored 10-pin connectors.

The tools are just Amazon specials from china. I didn’t see a need to go pro on this because I hope to never do it again.

Here's the inventory of wire:

Wire Gauge	Wire Color	Needed	Link	Length	Price	QTY	Total
10 AWG	Black	22	10 Gauge Black Marine Tinned Copper Primary Wire - 25 FT	25	$22.90	1	$22.90
	Red w/ White	8	Primary Tracer Marine Tinned Copper 10 Gauge AWG x 25 FT Coil - Red Wire & White Striped - USA	25	$23.56	1	$23.56
	White	8	10 Gauge White Marine Tinned Copper Primary Wire - 25 FTl	25	$22.90	1	$22.90
	White w/ Red	20	Primary Tracer Marine Tinned Copper 10 Gauge x 25 FT Coil - White Wire & Red Stripe - USA	25	$23.56	1	$23.56
Sub-Total		58		100		4	$92.92
12 AWG	Black	15	12 Gauge Black Marine Tinned Copper Primary Wire - 25 FT	25	$14.85	1	$14.85
	Black w/ White	16	Primary Tracer Marine Tinned Copper 12 Gauge x 25 FT Coil - Black Wire & White Stripe - USA	25	$16.56	1	$16.56
	Black w/ Yellow	22	Primary Tracer Marine Tinned Copper 12 Gauge x 25 FT Coil - Black Wire & Yellow Stripe - USA	25	$16.56	1	$16.56
	Blue	4	12 Gauge Blue Marine Tinned Copper Primary Wire - 25 FT	25	$14.85	1	$14.85
	Green	17	12 Gauge Green Marine Tinned Copper Primary Wire - 25 FT	25	$14.85	1	$14.85
	Green w/ White	4	Primary Tracer Marine Tinned Copper 12 Gauge AWG x 25 FT Coil - Green Wire & White Striped - USA	25	$16.56	1	$16.56
	Red	23	12 Gauge Red Marine Tinned Copper Primary Wire - 25 FT	25	$14.85	1	$14.85
	Red w/ Black	21	Primary Tracer Marine Tinned Copper 12 Gauge AWG x 25 FT Coil - Red Wire & Black Striped - USA	25	$16.56	1	$16.56
	Red w/ White	X	Primary Tracer Marine Tinned Copper 12 Gauge x 25 FT Coil - Red Wire & White Stripe - USA	25	$16.56	1	$16.56
	Red w/ Yellow	11	Primary Tracer Marine Tinned Copper 12 Gauge x 25 FT Coil - Red Wire & Yellow Stripe - USA	25	$16.56	1	$16.56
	White	5	12 Gauge White Marine Tinned Copper Primary Wire - 25 FT	25	$14.85	1	$14.85
	White w/ Red	9	Primary Tracer Marine Tinned Copper 12 Gauge x 25 FT Coil - White Wire & Red Stripe - USA	25	$16.56	1	$16.56
	Yellow	7	12 Gauge Yellow Marine Tinned Copper Primary Wire - 25 FT	25	$14.85	1	$14.85
Sub-Total		154		325		13	$205.02
14 AWG	Black	161	14 Gauge Black Marine Tinned Copper Primary Wire - 100 FT	100	$37.71	2	$75.42
	Black w/ White	42	Primary Tracer Marine Tinned Copper 14 Gauge x 25 FT Coil - Black Wire & White Stripe - USA	25	$10.44	2	$20.88
	Black w/ Yellow	30	Primary Tracer Marine Tinned Copper 14 Gauge x 25 FT Coil - Black Wire & Yellow Stripe - USA	25	$10.44	2	$20.88
	Blue	28	14 Gauge Blue Marine Tinned Copper Primary Wire - 25 FT	25	$9.93	2	$19.86
	Blue w/ Red	56	Primary Tracer Marine Tinned Copper 14 Gauge x 25 FT Coil - Blue Wire & Red Stripe - USA	25	$9.93	3	$29.79
	Blue w/ White	57	Primary Tracer Marine Tinned Copper 14 Gauge x 25 FT Coil - Blue Wire & White Stripe - USA	25	$10.44	3	$31.32
	Blue w/ Yellow	10	Primary Tracer Marine Tinned Copper 14 Gauge x 25 FT Coil - Blue Wire & Yellow Stripe - USA	25	$10.44	1	$10.44
	Green	112	14 Gauge Green Marine Tinned Copper Primary Wire - 100 FT	100	$37.71	1	$37.71
			14 Gauge Green Marine Tinned Copper Primary Wire - 25 FT	25	$9.93	1	$9.93
	Green w/ Black	57	Primary Tracer Marine Tinned Copper 14 Gauge x 25 FT Coil - Green Wire & Black Stripe - USA	25	$10.44	3	$31.32
	Green w/ Blue	21	Primary Tracer Marine Tinned Copper 14 Gauge AWG x 25 FT Coil - Green Wire & Blue Striped - USA	25	$10.44	1	$10.44
	Green w/ Red	52	Primary Tracer Marine Tinned Copper 14 Gauge x 25 FT Coil - Green Wire & Red Stripe - USA	25	$10.44	3	$31.32
	Green w/ White	65	Primary Tracer Marine Tinned Copper 14 Gauge x 25 FT Coil - Green Wire & White Stripe - USA	25	$10.44	3	$31.32
	Green w/ Yellow	15	Primary Tracer Marine Tinned Copper 14 Gauge x 25 FT Coil - Green Wire & Yellow Stripe - USA	25	$10.44	1	$10.44
	Red	32	14 Gauge Red Marine Tinned Copper Primary Wire - 25 FT	25	$9.93	2	$19.86
	Red w/ Black	54	Primary Tracer Marine Tinned Copper 14 Gauge x 25 FT Coil - Red Wire & Black Stripe - USA	25	$10.44	3	$31.32
	Red w/ Blue	90	Primary Tracer Marine Tinned Copper 14 Gauge x 100 FT Spool - Red Wire & Blue Stripe - USA	100	$37.58	1	$37.58
	Red w/ Green	2	Primary Tracer Marine Tinned Copper 14 Gauge x 25 FT Coil - Red Wire & Green Stripe - USA	25	$10.44	1	$10.44
	Red w/ White	3	Primary Tracer Marine Tinned Copper 14 Gauge x 25 FT Coil - Red Wire & White Stripe - USA	25	$10.44	1	$10.44
	Red w/ Yellow	8	Primary Tracer Marine Tinned Copper 14 Gauge x 25 FT Coil - Red Wire & Yellow Stripe - USA	25	$10.44	1	$10.44
	White	36	14 Gauge White Marine Tinned Copper Primary Wire - 25 FT	25	$9.93	2	$19.86
	White w/ Black	66	Primary Tracer Marine Tinned Copper 14 Gauge x 25 FT Coil - White Wire & Black Stripe - USA	25	$10.44	3	$31.32
	White w/ Red	4	Primary Tracer Marine Tinned Copper 14 Gauge x 25 FT Coil - White Wire & Red Stripe - USA	25	$10.44	1	$10.44
	Yellow	35	14 Gauge Yellow Marine Tinned Copper Primary Wire - 25 FT	25	$9.93	2	$19.86
	Yellow w/ Black	17	Primary Tracer Marine Tinned Copper 14 Gauge AWG x 25 FT Coil - Yellow Wire & Black Striped - USA	25	$10.44	1	$10.44
	Yellow w/ Blue	28	Primary Tracer Marine Tinned Copper 14 Gauge x 25 FT Coil - Yellow Wire & Blue Stripe - USA	25	$10.44	2	$20.88
	Yellow w/ White	17	Primary Tracer Marine Tinned Copper 14 Gauge x 25 FT Coil - Yellow Wire & White Stripe - USA	25	$10.44	1	$10.44
Sub-Total		1098		900		49	$614.39
Total				1325		66	$912.33

Edited June 11, 2023 by Matthew Abate

[Patcon]

That was my first thought. I have used some Sherco wire and it has a significantly larger OD than the factory wire. What I don't know is whether modern striped automotive wire has a smaller OD than the "marine" stuff gauge for gauge

[SteveJ]

The main reason behind the recommendation for marine wire was they seemed to have every combo needed.

I actually found a site last night that has GXL wire with tracers, but they don't have every color combo needed for the Z. 

Here's an updated list for wire colors:

BR	https://www.acdcwireandsupply.com/GXL_14_AWG_AUTOMOTIVE_WIRE_BLACK_W_RED_STRIPE_p/gxl-14awg-0103.htm
BW	https://www.sherco-auto.com/striped-tinned-tracer-primary-wire-14-ga-x-25-ft-black-wwhite-stripe-25-ft-usa-made-for-marine-and-automotive-use-also-in-25-ft-rolls.html
BY	https://www.acdcwireandsupply.com/GXL_14_AWG_AUTOMOTIVE_WIRE_STRIPE_p/gxl-14awg-0105.htm
GB	https://www.sherco-auto.com/striped-tinned-copper-tracer-primary-14-ga-x-25-ft-coil-green-wire-black-stripe-usa-made.html
GL	https://www.sherco-auto.com/primary-tracer-marine-tinned-copper-14-gauge-awg-x-25-ft-coil-green-wire-blue-striped-usa.html
GR	https://www.acdcwireandsupply.com/GXL_14_AWG_AUTOMOTIVE_WIRE_STRIPE_p/gxl-14awg-0403.htm
LW	https://www.acdcwireandsupply.com/GXL_14_AWG_AUTOMOTIVE_WIRE_STRIPE_p/gxl-14awg-0702.htm
LY	https://www.sherco-auto.com/striped-tinned-tracer-primary-14-ga-x-25-ft-coil-blue-wire-yellow-stripe-usa-made.html
RB	https://www.acdcwireandsupply.com/GXL_14_AWG_AUTOMOTIVE_WIRE_STRIPE_p/gxl-14awg-0301.htm
RB	https://www.acdcwireandsupply.com/GXL_14_AWG_AUTOMOTIVE_WIRE_STRIPE_p/gxl-14awg-0301.htm
RL	https://www.acdcwireandsupply.com/GXL_14_AWG_AUTOMOTIVE_WIRE_STRIPE_p/gxl-14awg-0307.htm
RW	https://www.acdcwireandsupply.com/GXL_14_AWG_AUTOMOTIVE_WIRE_STRIPE_p/gxl-14awg-0302.htm
RY	https://www.acdcwireandsupply.com/GXL_14_AWG_AUTOMOTIVE_WIRE_STRIPE_p/gxl-14awg-0305.htm
YB	https://www.acdcwireandsupply.com/GXL_14_AWG_AUTOMOTIVE_WIRE_STRIPE_p/gxl-14awg-0501.htm
YG	https://www.sherco-auto.com/striped-tinned-tracer-primary-14-ga-x-25-ft-coil-yellow-wire-green-stripe-usa-made.html
YR	https://www.acdcwireandsupply.com/GXL_14_AWG_AUTOMOTIVE_WIRE_STRIPE_p/gxl-14awg-0503.htm
YW	https://www.sherco-auto.com/primary-tracer-marine-tinned-copper-14-gauge-awg-x-25-ft-coil-yellow-wire-white-striped-usa.html
B	https://www.acdcwireandsupply.com/Gxl_Automotive_Wire_p/gxl-14g-01.htm
G	https://www.acdcwireandsupply.com/Gxl_Automotive_Wire_p/gxl-14g-04.htm
L	https://www.acdcwireandsupply.com/Gxl_Automotive_Wire_p/gxl-14g-07.htm
R	https://www.acdcwireandsupply.com/Gxl_Automotive_Wire_p/gxl-14g-03.htm

[Matthew Abate]

I’m going to start with the body harness and see what the impact of the larger outer diameter looks like. If it’s overwhelming I’ll figure something else out for the dashboard. The body and engine have the room to handle it, but the dashboard may have trouble.

[Matthew Abate]

I started assembling the body harness this week. I figure if the thicker insulation of the marine wire is going to be an issue it will be in the dashboard. The body harness doesn’t have to get crammed into a tight space the way the dash harnesses do, so I’m safe on this one.

I’ve cut the 15 main wires that come from the two connectors at the firewall to the same length as the original wires plus an extra 14 inches to allow for putting on my connectors and any discrepancies in my measurements as I go along.

For splicing I’m referring to a guide that my dad pointed me to. It’s a supplement written by Ford for for techs to work on ambient lighting in trucks and has some good diagrams for various types of splices. Here’s a PDF:

2013_truck_ambient_lighting_9-25-2012.pdf

Some of the splices are a little chunky for my taste, but they’re super strong even without solder, so I’ll continue referring to it. Here’s a finished Center Splice (the first example in the guide) connecting the door switch to the wire running to the room light without cutting any wires:

I’m using heat shrink on these to seal them up, but I’m also wrapping them with tape in the same colors Nissan used for referencing purposes. This particular tape came from Identi-Tape and is really nice and would probably be enough, but I have the heat shrink so I’ll use it too.

Edited June 23, 2023 by Matthew Abate

[SteveJ]

Thanks for the document. It's a good reference.

Keep going with the updates!

[dutchzcarguy]

21 hours ago, Matthew Abate said:

using heat shrink on these to seal them up

You should be able to buy them in the color you want.. tape is going to let go in 10 years or so...

You could also put a small ring of heatshrink on the end part of the tape.. so it stays better on! 😉 

[Matthew Abate]

Made some major progress today!

First, I was able to remove one of the colored connectors from the OEM body harness without any damage, and it looks like I should be able to source new spades for it with no trouble, so that’s a relief.

Second, I finished cutting and splicing the wires for the body harness.

 

Im not sure if you can tell, but mine is definitely beefier than the OEM harness. The overall circumference of all of the bundles together isn’t that much more, but it’s definitely weighs more.

So now I need to test all of my splices with a multimeter and then put zip ties at each of the branch points. After that is heat shrink labels on each end and the colored connectors, then on to the next.

Once that’s done for each harness I’ll lay them out and get the terminal connectors on, then wrap them.

[Matthew Abate]

Finished the wiring part of the body harness. All of the splices are strong and I have good continuity throughout, with no more than 0.20 Ω of resistance on any given wire.

All of the branch points are zip tied in the same locations as the OEM harness, so it should lay in just fine. The next step is a test fit inside the car to make sure.

Separately, I was wondering if anyone knows what the blue tape Nissan used to tack down unused optional wires is. I was thinking of using blue strap tape like they use on appliances, but if there’s a way to get the real thing that would be better.

[Matthew Abate]

I’m well and truly in it now!

I put the OEM color coded connector onto my new custom body harness, so I’m committed. No problems really other than putting the first terminal on upside down so the label wouldn’t have been visible. It was a pain to get off so I know my crimps are good. 😁👍🏻

Now I know not to shrink the labels until after the terminals are on the wire and properly aligned to the connector.

 

The shrink wrap labels are what I’m really showcasing here, though. I got this trick from a guy I knew in the IT team of one of my past jobs. They would label all of their Ethernet cables like this so they didn’t have to chase wires later.

These HSE label cartridges are what was holding me up. I had ordered 5.8mm, which looked really clean and tidy but is too small for this marine wire with it’s crazy thick insulation, so I had to order some 8.8mm. But it’s a breeze to put on. The only thing I would improve is making the label maker print on both sides, which is too much to ask for low end office equipment.

Heres my test fit with the 8.8:

 

Edited July 8, 2023 by Matthew Abate