@jfa.series1

8 hours ago, Namerow said:

I think that the 'ground wire' consists of the braided wire shown in this photo of the disassembled antenna assembly from my 1970 Z . The larger, toothed washer gets clamped between the assembly casing and the inside of the fender, while (IIRC) the smaller, smooth washer slips over the antenna mast. The purpose is to ground the mast...

Here are a few pics to help make @Namerow 's point.

On 5/17/2025 at 6:57 PM, Captain Obvious said:

And about that wire in the rear... The antenna has a ground connection on the wiring diagrams. I haven't been into that corner of an early car yet, but I thought (without actually seeing it), that antenna's ground connection came from being bolted to the body. Now that I see your harness, I suspect that ground connection to the antenna is NOT simply from connection to the body, but is in fact, a dedicated ground wire leading to the antenna.

Do you have an antenna for the car? Is there a ground lead bullet connection attached to it?

I've found several other similar issues with the factory wiring diagrams. In many locations, they didn't do a good job of conveying how grounds were connected.

And lastly... Yes, the early rotors had holes in them. Aftermarket replacements did away with that, but they are an early car thing.

I just checked the wiring harness from #6521 and it does not have the extra wire that @motorman7 was asking about. I also pulled out the antenna that I had installed in that car back in 1980. I got it from my local Datsun Dealer, all they could get was one for an early 280Z. That one has two power wires plus a ground wire. I didn't use the ground wire and just let it ground by the mounting bracket. Here's a pic.

I also have a spare one from the lot of parts that came with #957. It has only the two power wires, no ground wire.

Here's a couple of pics of my wiring harness from #6521, without the ground wire, with both antennas and the speaker.

Edited 17 hours ago17 hr by CanTechZ

The wiring pigtail for my 70 Z's antenna also consisted of just 2 power wires (i.e. no ground wire).