I've poked around looking for a wiring diagram for the early cars (1970) and haven't come up with anything really good. I've turned up five diagrams so far, and they all are questionable in accuracy.

This is clipped from a 1970 owners manual:

This is another version, supposedly from the owners manual:

This is clipped from a 1970 Factory Service Manual - Body Electrical section:

And here are  two versions clipped from the Service Manual Supplement, which I believe came out for the 1971 model year:

Anyone got anything different than the above before I take one of those and try to make improvements? Clean it up and fix the issues I've found (when compared to the car I'm working on).

Several years ago, I worked with your #2 schematic ("Datsun Factory Parts are fully warranted to give utmost satisfaction") and then added editing comments, using the wiring, connections, and devices in my car (unmolested 4/70 240Z) as my primary guide.  See attachment #1.

Back in 2015, CZCC member @EuroDat (Chas) did a beautiful job of creating a full-colour wiring schematic based on the specs for MY-1970 USA-Cda cars (see attachment #2).  It addresses most of the issues that I identified in my own review.

S30 Wiring Schematic - 70 240Z - B&W - 70 Owners Manual - Comments added for errors 7.pdf S30 Wiring Schematic - 70 240Z - Colour - Eurodat.pdf

While I'm at it, here's my edit of the mini-schematic for the Combination Switch, corrected to reflect what I found in the actual layout of the wiring and contacts in the Combination Switch installed in my 4/70 car.  I started with the mini-schematic that was part of large wiring diagram included with my car's Owners Manual ("20-Mar-1970  -  030300  -  OM0E-0S30U2") and then made corrections...

Note on the left side of the diagram that I have two columns of wiring colours:

The left column indicates the colour of the wiring on the vehicle side of the Combo Switch connector.

The right column indicates the colour of the wiring on the Switch side of the connector. 

'SPD' = spade-type wiring connector

'BLT' = bullet-style wiring connector

Edited June 30, 2024Jun 30 by Namerow

Thanks for the files. I'll look that stuff over and see how they look!  

Namerow, So here's my assessment at this point... I should have asked earlier because I independently found most of the issues you noted on your markup.  Asking sooner would have made that easier.    Those issues are why I was expressing frustration with the documentation.

One big issue, however, is your interpretation of the power going through the "F" fuse. That fuse feeds FROM the ignition switch, it towards it. The rest of stuff (turn signal flasher, and gauge power) is fused. And of course, that also means that the comment about the fuse block nomenclature is also incorrect when you said that top row are all power-out with the exception of "F". The entire top side IS power-out, including "F".

And many of the problems I turned up still exist in the color version. Maybe @EuroDat can pop in here if he caught wind of this tread? This could be an opportunity to make that document better.

Oh, and the existence / non-existence of the accessory relay... I was wondering if maybe that was a build date issue, But if you have the accessory relay on your 4/70, then even if it was added after initial release, it was added pretty early. 

@Namerow So independent invention... Here's what I've been messing with. I cleaned up and modified the diagram from the BE section of the FSM. Biggest changes are adding the accessory relay and it's associated devices (heater blower and rear defroster). Lots of other smaller changes, most of which you identified in your notes.

I will make additional changes based on stuff you found that I did not such as the incorrect labeling of the gauge functions (didn't see the forest through the trees) and it seems there are some issues around the combo switch area where documentation does not accurately depict reality. 

 

Edited July 10, 2024Jul 10 by Captain Obvious

Here's the latest. I swapped the gauge locations and made a couple other small changes. Please let me know what you think:

<V2.0>

Edited July 10, 2024Jul 10 by Captain Obvious

Hi guys, Just quickly dropping in to let you know, I'm still around. I'll read through the thread in more detail later the weekend.

Glad you're still around!

I spent some time looking at the details of the power distribution system and cobbled up this sketch:

And I made some changes to the wiring diagram I've been messing with.  Here's the latest:

<V3.0>

Edited July 10, 2024Jul 10 by Captain Obvious

And I have a question... On a future revision, I'm intending to clearly show the coil and ballast resistor on the engine side of the bulkhead firewall. But what about the reverse light switch.

Do the wires going to the reverse switch on the transmission go through the same firewall bulkhead out towards the engine, or do they go through a hole somewhere else? I haven't looked for those on my car, but hoping someone here knows off the top of their head.