SteveJ

Okay, you guys have my attention now. Thanks, @kully 560 & @HusseinHolland!

It doesn't seem to be an impedance mismatch

It wasn't that long ago that I made the video. I'm pretty sure I talked about the vacuum control and where it went.

@HusseinHolland If you go to my YouTube channel (myZcarlife), I have a short video where I show the features of the stock AC controls/evaporator. If your system doesn't have those features, it's not stock.

Since you're going down that path... Most non-industrial facilities in the US are bringing in 208VAC (two phases off a WYE transformer). At the entry point for the facility (service entrance), there is a neutral (return path) bonded to ground. That is put in the circuit with one of the legs of the 208VAC to provide 120VAC. In Canada, instead of using 480VAC as low voltage, they use 600VAC. The fun part is to source parts in North America for equipment to ship to a 50Hz country since almost everybody in North America publishes specifications for 60Hz. The most fun was a project where all of the equipment downstream operated at 60Hz. The generators operated at 60Hz, and it was being installed in Europe. They had to place equipment in between the utility and our equipment to go from 50 to 60Hz. Ships have to deal with this, too. For instance, the US Navy ships are designed to support voltage and frequency used in America. When they get shore power while docked in foreign ports, they have to have the frequency converters between the shore and ship. Going back to @chaseincats (to pretend that this rambling is still a little on topic), as @Racer X explicitly said, match impedance between the stereo and speakers. Mismatched impedance will work, but not as well.

The early 260Z has the same dash as the 280Z, as indicated here: https://www.carpartsmanual.com/datsun/Z-1969-1978/body-260z-280z/2-seater/instrument-dash-side The 73 240Z dash is different from the earlier dashes.

Yes

Does the stereo manual specify 4 or 8 ohm speakers?

When @240260280 was showing me how to adjust the valves, some were so tight that we both were pulling on it to break it loose.

Heck, you could drive up to my neck of the woods and use my 20T arbor press.

If you're getting a steady medium to bright light off a test light, yes.

What exactly are you trying to do? It sounds like you're looking for a non-existent problem.

Not specific to @HusseinHolland's question, but the valve used by @Captain Obviousdoes appear to be from a 2000 Acura TL. https://www.rockauto.com/en/moreinfo.php?pk=6636476&cc=1361090&pt=6860 As for the dead photos, blame Photobucket. Now @Mike generously hosts more photos on the server so we can include images that aren't dependent upon outside services.

FYI: They are available via Rockauto: https://www.rockauto.com/en/parts/stabilus,3B250273,lift+support,1404

Then the car is not the problem. It's either a component (stereo or speaker) or wiring issue.

Do you have the problem when the key is in the accessory position?

The $29 must have been in Canadian dollars. 😉

I found the Littelfuse brand strip fuses that should fit the VW link box above on DigiKey and Mouser. Apparently the style is called HSB, and they are available in ampacities that are suitable for the Z. I'll definitely consider it for when I build the engine harness for my 240Z.

Also I have thought about playing around with this: https://www.amazon.com/gp/product/B00902G49U It has four slots for fusible links and a plug that is connected to ATO fuses. It would be a matter of figuring out where to mount it to reach the battery.

@HusseinHolland I saw this on Reddit Just Rolled Into the Shop and thought of you.

There is nothing that would affect polarity at the transmission. Testing: Get the car where you can safely get underneath. Put the transmission in reverse with the engine off. Disconnect the reverse switch from the wiring harness. Use an ohmmeter to make sure there is continuity across the switch with the transmission in reverse. From the voice of experience: @Zed Head helped me figure it out with the reference drawings.

What do you mean by the wires on the reverse lights are switched? Where do you think they are switched: at the transmission or at the tail light?

I can't put my finger on it, but something about your solution appeals to me more than the one done by the IPO (idiot previous owner).

The problem is that for the one relay you need a dual coil and a suitable relay base. You won't find that in a Bosch style relay. If you are lucky, you might find such a relay made for another car, but you would still need to add the base if you can find it. You will probably end up using two relays or doing the smart thing and staying with the factory style relays.

Aftermarket quality on mechanical fuel pumps has been abysmal. I tried one on someone's car. I removed it and used the diaphragm from it on the old fuel pump. The old fuel pump was fine with the new diaphragm.