Zed Head

We're teaching how to wire a fish. It's complicated.

Deleted some wrongness. I would just use the R, B, S, and IG to decide what to use to power your Haltech and parts. Believe Steve. That would be a great political slogan...

The diagrams never show the colors from the device, only the colors in the main harness. So you'll have to use the plug to convert from device harness to main harness. I screwed up and used the 74 260Z diagram. Deleted those pictures. Steve is on the proper car. Oops.

More sales. BAT might be the best thing that has happened for old car sales in decades. https://bringatrailer.com/listing/1981-datsun-280zx-21/ https://bringatrailer.com/listing/1978-amc-matador-barcelona-coupe-last-matador-built-1-of-1/ https://bringatrailer.com/listing/1978-datsun-280z-98/? https://bringatrailer.com/listing/1977-datsun-280z-58/ https://bringatrailer.com/listing/1967-buick-skylark-7/

Your tools look right but you can probably use the splines for the Vise-grips. I think that's why they are there.

Pop the little screw out, put a Zerk fitting in and grease them up. They'll probably last another 50,000 miles.

If the windshield seals leak that's where the water path is to the floor, depending on at what angle the car is parked.

Used Nissan u-joints are often tighter than new aftermarket u-joints. "New" does not always mean better.

No, it was No Good. I had a spare. Your relay is a typical 4 pin relay (two of the pins in yours are connected, that's why you only have three terminals). You can buy them for a few dollars at any auto parts store.

Use a screwdriver and pliers and bend these two tabs back. The board with the parts on it will come out. It will probably look like this inside.

Forty-five five for a red seventy-three. Pretty good.

Lime-olive green? https://bringatrailer.com/listing/1973-datsun-240z-157/

Can't be sure. Not looking good. If you're getting power at the horn button wire then the connections on the way to the horn wire should be good, they use the same plugs, in and out. It might be that the light is going out because the solenoid coil is bad. The heat from grounding the circuit opens the circuit. Can you trace the green wire from the C-6 connector and see if it gets to the horns? That would be a clue.

The test light probably goes out because you're measuring the side with the resistance of the solenoid coil. When you complete the circuit and the current passes through the contacts the voltage through the solenoid drops too low to light the light. What kind of test light do you have? Another way to test the horn relay would be to connect it to one of the horn wires, at the horn location at the front of the car. Then press the button. The light should light. If it does the relay works.

It might, I'm not sure. I'd use a short Phillips head and see if could get the screws out. Or a long one, sometimes a long blade will reach through the morass and get to the screw heads. Looks like two and it should fall right out.

Should also hear the relay click if the horns are not too loud.

Only if the green wire has a good ground circuit.

Find the wires with the right colors. Green, green w/red, green w/black.

Do you have a small bumper 260Z or a big bumper 260Z? Maybe you should be using the 1975 280Z FSM. 260Z was a changeover year. Here is 1975. Maybe it has a clue. The location of the fuse box might help, for reference, and the vent pull.

Probably not the horn relay. You keep showing the picture with four black lines on it. What is that picture supposed to illustrate?

These guys have added a new feature to their graphics. Vaccination rates by county. Pretty interesting. https://covidactnow.org/?s=1971887

You shoulda said something... https://nostalgicac.com/datsun-240z-260z-280z-compressor-upgrade-kit.html

That's a popular one for the Z cars. There is info on the site about it. Here's one.

It's a rebuilt head, probably on a rebuilt short block. The N47 with flat tops would give a high CR. I don't think Nissan did that for their factory engines. Looks like somebody's home project. BRE probably stands for Big Ron's Engineering and Speed Shop.