SteveJ

You only need to jumper the ones you did to get continuity. Everything else can be left disconnected.

Okay, I had to dig through the 73 wiring diagram. That looks like the K18 relay. If the relay has failed or lost its ground, then the car won't start. That's part of the nag warning for the seat belts. While it's present in the 72, the circuit didn't make it into the wiring diagrams. You can get this connector from Vintage Connections (https://www.vintageconnections.com/products/6-3mm-connectors?variant=46131501236545) and make a nice, plug-in jumper.

First check the jumper. Make sure it's still in place. Next, you want to make sure you have continuity in your wiring harness between the ignition switch connector and the solenoid. You want to make sure the dash harness to engine harness connector is still connected firmly (and free of corrosion). This is the connector you are looking for: You might have to get some help to test the entire length. One way of testing is to take the BY wire off the solenoid and make a jumper wire to ground it. Then see if you have continuity to ground at the ignition switch connector. I cheat. I have long enough leads to test wires from the front to back of my Zs.

Year of car? Was it originally manual or automatic? Please go here and click on the link to create a signature. https://www.classiczcars.com/settings/ Include information such as the year of your car and any known modifications. It helps a lot with troubleshooting.

The key piece of missing information: What is the voltage to ground at the WR wire? If there is no voltage at the WR wire in a 240Z there are two primary causes: The fusible link is bad. The ammeter gauge is bad. Does your horn work? Do your hazard lights work? Do your brake lights work? If the answer to all 3 are "no", then look at the fusible link. Next: If the answer to any of those 3 is "yes", then do you have power at the cigarette lighter? Do your running lights work? Does the inspection light work? If none of those circuits work while you have hazards, horn, or brake lights, then it's quite possible the ammeter gauge is bad. (Note: I have seen a couple of real-life cases where the ammeter gauge blew because someone connected a battery backwards.)

When you get the horns back, look for my video I did on horns. It may aid in reassembly. https://youtu.be/oOHLgH1o-oE?si=Cle_9Ey2BWmjFxZU

The condenser served two purposes. It prevented premature wear on the points (240Z only) and it reduced electrical noise. Electrical noise is really more of a problem for AM radio than a modern FM radio. The ignition system won't even notice if the condenser isn't there.

And I just did a search on FB. Many people in the Georgia Z Club identified it as a scam.

Classic scammer tactics. Move on.

I finally remembered to upload the wiring diagrams from the FSM. There are some errors. The intermittent wiper relay wiring is wrong on the diagram. The 74 manual corrected the errors. I can't recall other errors off the top of my head, but Matthew Abate and I were running across them as he tried to rebuild his wiring harness. 73 Wiring Diagrams.pdf

I don't know if the 71 had the seat belt warning. I think the headlights may have constant voltage with the headlight switch completing the ground path. In the 72 & 73, the headlight switch connected the positive with the fuse box with a red wire. There may be some other differences that I haven't tried to determine.

The funny thing is that many people at work have seen my 260Z since I used to drive it in to go to club meetings immediately after work. A few people asked if I had painted the 260Z thinking the new Z was the 260Z. The two main roads that lead to my neighborhood both have construction going on in different places, so on my commute home, I might take a roundabout way home even if it takes longer so I don't have to sit in traffic. There are also more curves, so that is a plus.

I would still remove the valve cover. If you find signs of scratching on the cam, you can figure it also happened to the bearings on the crank.

To piggyback on @Captain Obvious's reply, look for debris on top of the head and any signs of scratches on the camshaft when you have the valve cover off. Like @Patcon, I was thinking bearings. I've been regularly watching the engine teardowns on the YouTube channel I Do Cars. When I saw the photo, I just heard the host of that channel saying, "Forbidden glitter". That's his phrase for finding the remnants of chewed up bearings. With the pan off, did you happen to check the rods for play?

Fuse box. If you don't have a cover on your fuse box, copy the picture below to your computer and consider printing it: Or this: What I see in your photo is that someone put on some butt splices to connect wires. Unfortunately some people hack into wiring harnesses like that. You could tap into another circuit, but since you don't seem to have much electrical knowledge, I suggest you don't. Most people don't know how to splice into existing circuits properly, and that causes more issues. It's kind of like the problem you have now. Amongst other problems you can create is that you could cause a fuse to blow more often if there is more of a load than the circuit was designed for. The First Rule of Holes: When you want to get out of a hole, the first thing you should do is stop digging. There are references in the downloads section that include a PDF of the factory service manual. The BE section has some good information on the electrical system. If I can remember, I'll also upload a clean scan of the wiring diagrams I did from my copy of the FSM. Diagnose the circuits. Do you know how to use an electrical meter? If not, find some Youtube videos to start learning. Today is a great day to learn something new. You don't have a bezel. Here's the bezel: https://zcardepot.com/products/map-lamp-light-bezel-240z?_pos=1&_sid=bd9927824&_ss=r My guess is that you're also missing the screws. https://zcardepot.com/products/map-light-bezel-screw-240z Keep posting photos with your questions. It does help in composing responses.

The stock circuit has a red/blue wire and a black wire. The red/blue comes off the fuse for the dome light. It is always hot. The map light housing is white.

I suggest you pull the oil filter and open it, too. This is not a good sign.

I figured I would let the cat out of the bag. From September 2020 at the unveiling, I thought that Nissan finally designed a Z I would want to buy new. I was too young to buy an S30 or S310 new. I was young and broke when the Z31 and Z32 came out, and I never was really taken by the Z33 or Z34. Yes, the RZ34 is a Z34 with a new wrapper, but I really liked the heritage touches. To me it looks more like a GT car and less boy racer. When I talked to a couple of Nissan people during the pre-sales road shows, they confirmed New Sight Orange would be coming. The first Z I remember was a 260Z in New Sight Orange. It was owned by a former NASA test pilot, and I lived down the street from him. A friend's father bought the car and got it back on the road. My friend got to enjoy it for a few years before the car was hit by an uninsured motorist. My first Z, a 73 was originally New Sight Orange, though someone with questionable taste had it repainted a color similar to Metallic Gold, though it looked worse than a MAACO paint job. I still have that car and hope to return it to New Sight Orange some day. I was excited to hear that Nissan was holding to its word that orange was coming back, but my excitement diminished when I learned it was on the Heritage Edition only with a sticker of $62K (plus whatever the dealers think they can charge for a special edition). So I set about looking for an alternative. I noticed that dealers were finally coming off sticker price for the Z. On the other hand most of those Zs were Gun Metallic. While I don't worry too much about color, I didn't really want grey. No blue Zs with manuals were popping up nearby, but finally a Z in Sport trim showed up at one of the closest dealers sporting Ikazuchi Yellow Pearl paint. I took it for a test drive, and the wife loved it. It felt right for my new daily driver, so a couple of hours later I drove it home. The new Z has very good acceleration as one would expect with 400HP on tap. The steering feels extremely light at low speeds, but the feel improves as speed increased. With no limited slip, it's easy to spin the tire a little getting into traffic. The seats are comfortable, and the shifter is in easy reach. The clutch engages higher than I think it should, but I am just going to live with that. The blind spots are huge, but the blind spot warning system seems to work well. The view out the rear window is small, too. I have an Android phone, so one of the USB slots is taken by the phone if I want to use navigation. If you want more creature comforts, or if you are planning on tracking the car, go for the Performance trim. The yellow pearl paint stands out, but it doesn't look like a taxi, even with the black roof. I have experienced one problem with the car so far. Yesterday, the TPMS monitoring system lost communications with all 4 tires. I drove the car around for a while, and the system found the left front, though that didn't last. I guess I'll see how good the local service department is.

I recently visited with @inline6 to see if I could help him with an issue with his wiper motor. Though we thought we fixed it, my meter readings said we still had a problem. It turned out to be a self-inflicted issue that @Captain Obvious helped me to understand. Thanks to @inline6 finding an old thread (linked below) and @Captain Obvious getting me to focus on the diagram in the FSM, I was able to develop a better understanding of how the wiper circuit works. I hope I can convey it clearly in this thread. Anyway, here is the thread @inline6 found: Page BE-17 of the 72 FSM shows the wiper circuit, but it is confusing because it is a challenge to relate the diagram to the physical layout of the components. It also shows how the circuit is when the wipers are parked. The motor is not in the first photo, but the relay clamps to the motor, and the gearbox attaches to the motor. The relay is a 3-pole, double throw (3PDT) relay. In it's de-energized state, the contacts connect the motor to run in reverse for parking. The cap on the gearbox has a blue/red wire and red wire. The picture above is for a 73, but it was the clearest picture I could find. If you look carefully, you can see two rivets on the cap. On the other side of the cap, there is a set of contacts. These contacts allow the gearbox to break contact between the armature and ground when the wipers are parking. The gearbox has a wheel on the back with a raised area to push on the contacts. When the switch is turned on, the relay is energized. The blue arrows in the diagram below show going from the positive of the battery to the motor. The green lines show the contacts closed. The return path from the motor to ground depends upon the position of the wiper switch. If the switch is in low, follow the brown arrows. If the switch is in high, follow the red arrows. When you turn the switch off, the relay is de-energized. The contacts in the relay go back to the normally closed position. This reverses the power flow through the wiper motor. The motor keeps going until the wheel in the gearbox comes into contact with the contacts in the cap. At that point, the current return path for the motor armature is opened up. (Actually, both sides of the motor see the positive wire. This isn't an easy circuit to understand, especially if you've never taken a wiper motor apart.

That was all part of the 70s effort to annoy people into wearing seat belts. It got even worse in 74 as everybody was required to integrate seatbelt interlocks with the starter circuit. People got very perturbed that a bag of groceries in the passenger seat kept you from starting the car until the groceries were safely buckled in. You can even still see interlock in the 75 wiring diagram though the NHTSA rescinded the requirement and every automaker immediately ditched it.

The subharness for the fuel pump that Nissan designed for the 73 when trying to solve the issue of vapor lock consisted of two 4-pin relays. The power for the coil in relay 1 came from the neutral between the VR and alternator. It is a yellow wire. The power for the coil in relay 2 was the black/yellow wire from the starter solenoid. FP relay 2 was normally closed and cut power the fuel pump during starting. These two relays were mounted on the passenger kick panel with the wiper relay, horn relay, and AC (fan) relay. The device shown by the OP is mounted under the center console on the driver's side.

I'm thinking it might be the buzzer for the seat belts. My 73 has the same device.

Year?

I believe you'll find that the interior panels are going to be more like the 280Z (75-76) than the 240Z. If I can remember to take photos of my 260Z when I get home, I will post them. Then you can visually compare them to the 240Z trim panels.

I think I know someone in the local area who has knowledge of tracing electrical circuits.