1973 240z Custom Wiring From Scratch

[SteveJ]

I do believe that is part of key in ignition buzzer.

[Matthew Abate]

13 minutes ago, SteveJ said:

I do believe that is part of key in ignition buzzer.

Do you mean this guy? - https://maseraticompound.com/products/datsun-240z-series-1-anti-theft-buzzer

Edited January 22, 2023 by Matthew Abate

[SteveJ]

I've never taken the dash apart enough to find the bastard, so I'm not sure what it looks like. I just know that mine would work randomly.  

[Matthew Abate]

I guess what I am worried about is whether or not I need to complete this circuit in order for other things to work, and it is sounding like that isn't an issue.

[SteveJ]

6 minutes ago, Matthew Abate said:

I guess what I am worried about is whether or not I need to complete this circuit in order for other things to work, and it is sounding like that isn't an issue.

Yeah, the buzzer doesn't affect anything else.

[Matthew Abate]

3 hours ago, SteveJ said:

Yeah, the buzzer doesn't affect anything else.

I just noticed some other goofiness related to this: In the wiring diagram I downloaded from this site, the yellow wire coming off the buzzer connects to the R/L wire coming from #7 on the wiper switch which splices to a R/L wire for the step light and continues on to the fuse box.

Great, except in my harness the R/L wire coming from the wiper switch connects to directly to the engine harness (no splices) and then turns into w L/Y wire for the wiper motor.

I think this is related to the missing YL & YB wires I see on my wiper switch that I mentioned earlier. Gotta do some more sleuthing.

Edited January 22, 2023 by Matthew Abate

[Matthew Abate]

This post is just for documentation purposes and to put a bow on some things I have brought up over the last few days…

I retraced the Red wire with a Blue stripe coming out of my wires switch and confirmed that it 100% does not go to the fuse box. It goes to the center pin on the 9-pin connector on Dashboard Harness 2 (the one with all of the lightbulbs on it). That center pin on the 9-pin connector on the harness goes to the black connector that connects to the Engine harness. Note: in the FSM this connector is white. The white one on my harness is black in the FSM. I verified this by the wires they contain and by the shapes of the connectors, which are unique. That pin on the black connector switches to a Blue wire with a Yellow stripe on the engine harness and goes to the 6-pin connector for the wiper motor.

Also, there is no second buzzer in the wiring diagram in the 1973 FSM. Just the single 3-wire buzzer with the 3-pin connector, which I have accounted for.

In the FSM, the "STG Lock SW" I keep bringing up has a Red wire that is spliced to a Re wire with a Blue stripe running to the left step light as well as some of the dashboard lights (map light, glove box light, room light) and ends at a 6-pin connector for the fuse block. That pin has a second Green wire with a Blue stripe that runs directly to position #2 on the wiper switch (after a color change to Green with White). The connector on the Fuse Block also swaps colors to Green with White ( ¯\_(ツ)_/¯ ). I already mentioned that the Black wire on the "STG Lock SW" runs directly to the left door switch.

On page BE-23 of the FSM, it states, "The steering lock is combined with the ignition switch to a single unit which contains warning buzzer micro-switch for reminding the [driver] to lock the steering. The microswitch is connected to a warning buzzer." This corresponds to what @SteveJ has said. On the next page it mentions the ALR, which is not in any of the diagrams…

Quote

The warning buzzer is common between key lock and A.L.R. (auto-lock retractor). It operates if the door is unlocked with the key inserted in the steering lock. When it becomes necessary to repair a buzzer, it is essential to make reference to auto-lock retractor circuit. The buzzer is installed on the instrument [panel] support bracket.

The two wires I have in the harness go to this integrated steering lock. The reason I can't find it in my stuff is that I don't have one. I have one from an older car.

Here's what the one for a 1973 240Z should look like (note the two wires coming off of it with spade connectors):

And here is what I have (note the lack of the two wires):

Here's a picture of a different version I found on new-datsun-parts.com, probably from an older year (note the plastic ring with the two wires, i.e. non-integrated steering lock):

So, questions answered. I just need to find a 1973 ignition switch or the non-integrated one mine is missing for the problem to be solved.

 

In other news, the Comb. Switch in the FSM for 1973 is pretty different from 1973 wiring diagram I downloaded from this site. First, the positions are only numbered for the first four wires (1, 2, 19, & 20). In the FSM, the wires from top to bottom are:

• GL (Labeled as Position 1)
• GW (Labeled as Position 2)
• WR (Labeled as Position 19)
• R (Labeled as Position 20)
• B
• RL
• LY
• LW
• YB
• L
• LR
• LW
• B (back side)
• B (back side)

There are 14 lines running to the box denoting the Combination switch, with 12 color labels. There are 13 rows showing the jumpers in the switch and how the mechanisms route electricity to the wires. The 13th row is dedicated to one of the 2 black wires coming out the other side of the box to connect it to the TS switch, as discussed, and does not go to the GB wire going to the horn.

When looking at my actual switches, there are 14 pins across 6 connectors on the wiper switch, two of which connect to each other. They are:

• 9-Pin Connector
  • GL (Goes to Body Harness, Fog Light Switch, Radio, Rheostat, & Cigar & Hazard Fiber Optic Light Source)
  • GW (Changes to GL and goes to Fuse Box, as mentioned above)
  • RL (Goes to the Engine Harness where it changes to LY and goes to the Wiper Motor) 
  • LY (Goes to Engine Harness and terminates at the Intermittent Relay)
  • LW (Goes to Intermittent Relay and splices to wires going to the Engine harness and ending at the water tank)
  • L (Goes to Intermittent Relay)
  • LR (Goes to Engine Harness and branches to the Wiper Motor and Reverse Light Switch on Transmission, but I need to verify this)
  • YB (Goes to the Engine Harness where it changes to B and goes to the Wiper Motor)
  • YL (Changes to LW at the connector and goes to the Intermittent Relay and the Engine Harness where it goes to the Wiper Motor)
• Spade Connector
  • G (Splices to many other black wires that run to various dashboard & center console instruments, the Rear Window Defroster Relay, and the Engine harness, terminating at the Alternator)
• Bullet Connector #1
  • WR (Splices to WR or L wires going to Alternator, Defrost Relay, Fuse Box, Accessory Relay, Ignition Switch, Ammeter, etc.)
• Bullet Connector #2
  • R (Goes to the Fuse Block, then to the Engine Harness and ending at the Fog Lights)
• Bullet Connector #3
  • B  (Connects to Double Bullet Connector)
• Double Bullet Connector
  • B (Connects to Bullet Connector #3 and to a B wire on the TS Switch)

Edited January 23, 2023 by Matthew Abate

[Matthew Abate]

I updated the diagram for the Combination (Wiper) and Turn Signal Switches to match the samples I have on hand and the 1973 FMS:

The Red text needs better labeling. I went with what is in the FSM where I could for now. Also, in my sample, #2 (Blue with a White stripe) is actually Yellow with a Blue Stripe. It changes to LW at the connector and goes to the Intermittent Relay.

Edited January 23, 2023 by Matthew Abate

[Matthew Abate]

Now that I am almost done verifying (and fixing) my documentation of the two dashboard harnesses I just have one last thing to do one the dash: figure out where the resistor for the Tach is supposed to be. I just traced everything from the Tach and Ignition Switch plugs on the dashboard harness all the way to the ballast resistor on the engine harness and I am not seeing one. I took a look at this thread and the photos that @zKars posted on page 2 look like it is located on the engine harness just inside the cabin, close to the colored connectors, but that's one of the 2,200Ω resistors on a 280Z:

On 5/16/2020 at 10:35 AM, zKars said:

For the sake of reference, here are pictures of the resistor's where-abouts and appearance in the harness.

located just inside the firewall grommet.

 

Unfortunately, I don't have anything even approximating this on mine. I thought maybe my dash is from a different year, but the FSM for the '72 shows a 0.5Ω resistor between the ignition and the tach. The '73 FSM shows a resistor wired up the same way, but does not indicate how many ohms of resistance if provides.

I found a resistor on the 1974 FSM diagram and it is on the engine harness on a Blue wire, similar to the photo above, that runs to a splice to the Full-Transistor Ignitor Unit, and the Ignition Coil, but I am not sure this serves the same purpose.

I'd like to figure out how it is supposed to be set up on the 1973 harnesses, but I also need to figure out what I should do for my final setup because I have a 280ZX distributor with a E12-80 Ignition box and I would like to make my regular 1973 tach work with it rather than doing a bunch of unnecessary modifications there, per @Zed Head's recommendation.

Edited January 23, 2023 by Matthew Abate

[SteveJ]

That's the ballast resistor.

So conventional wisdom says the 4 wire tach won't work well with the ZX ignition. I didn't have the ZX ignition in my 240Z long enough to confirm it. I have the Pertronix with no ballast resistor and no issues with the tachometer.

If you wire the car with fidelity to the FSM wiring diagram, you would need to do the following to go with conventional wisdom:

1. Swap 280Z tach internals into the 240Z tach. 
2. Jumper the black/white and green/white wires at tach connection in the dash harness.
3. Run a wire from coil negative to the tachometer and have a 2.2k Ohm 1/2 watt resistor between the coil and the tachometer.

[Matthew Abate]

Ooooh, duh. Okay, yeah. Not sure why I didn’t realize that. I‘ve gone around a couple of times on the topic of the tach mod. Some people insist that the tach needs to be upgraded and some people insist that it doesn’t. Either way I will work this out later in the process and proceed with the engine harness.

Edited January 23, 2023 by Matthew Abate

[SteveJ]

8 minutes ago, Matthew Abate said:

Ooooh, duh. Okay, yeah. Not sure why I didn’t realize that. I‘ve gone around a couple of times on the topic of the tach mod. Some people insist that the tach needs to be upgraded and some people insist that it doesn’t. Either way I will work this out later in the process and proceed with the engine harness.

Meh, it's just one of those senior moments we all have from time-to-time, like all of the times I couldn't get the car to start because I failed to put the wire back on the coil.