Wiring harness questions - early '71 240Z (long)

[Arne]

One note, your car may have been built before the wiring harness was modified to accept the kick down switch that the AT requires, which differentiates the AT from the MT harnesses. However, the difference is only ONE wire, so you CAN make an AT harness from a MT harness by adding one wire. Presumably, you can invert that (AT to MT) as long as you are referring to the Dash Harnesses only.

My car is an automatic, but will have a four speed later next summer (assuming I get the wiring debugged), so the presence or lack of the kickdown wire is immaterial to me.

As far as someone making new harnesses, I think the biggest problem is the several dozen variations that existed coupled with the fact that not everyone is willing to spend $200 for a dash harness, or .... It seems that as important as this component is, everybody feels that it should sell cheaply, yet it's one of the harder parts to replicate due to the investment in materials required, which in turn makes it expensive.

Agreed. I paid several hundred dollars (in 1992 dollars) for the harnesses for the MG, but they were worth every penny. Even as good as most of my wiring is, for daily reliability I'd be willing to lay out some serious cash for BRAND NEW harnesses, if they were available. But if used is all I can get, I may as well keep the ones that I already have that are decent.

Thanks for all your info, Enrique. If you make it down to the Eugene area some time, look me up. I'll have a nice, dark homebrew waiting for you.

[beandip]

Arne, here is another sorce Idaho Z Car (208-466-0004) They have lots of Z and I think he can come up with what your looking for . Gary

[Arne]

Arne, here is another sorce Idaho Z Car (208-466-0004) They have lots of Z and I think he can come up with what your looking for . Gary

Thanks, Gary. I'll try him as well when I shop. Before I start contacting vendors, I want to re-verify the part numbers. Probably won't get to that until the weekend.

[Arne]

Got under the dash this afternoon (once the ice melted - damn freezing rain), and was finally able to find the part numbers on the two dash harnesses. They are 24013-E4705 & E4706. I suspect that these two are the ones with the extra wiring for the automatic transmission (which my car still has for now). What I'd like to find out is whether there is a manual transmission equivalent to these two parts that I could use instead, since I will end up swapping in a 4 speed next Spring. Since I don't yet have the parts CD (I will buy it after the holidays, I promise), could someone who already has it look up the dash harness numbers for a 10/70 build date car, both auto and manual for me? I'm betting the auto harnesses will be the E4705 & 06, and that the manual may be E4650 & 51. If it is serial number specific, my car is #12746.

[Arne]

Here's the latest I've learned on the dash harness deal.

• While the two dash harness pieces are separate, and have individual part numbers, Nissan apparently never offered the two parts separately, but sold them as an assembly under a single part number.
  
• Apparently, all three major wiring harness parts (engine, dash and rear) were different on the automatic cars. It is not known whether any of the manual transmission harnesses could be successfully connected to any of the automatic pieces. It is therefore probably best for me to either find the correct automatic dash harness assembly, or to consider changing all three sections to matching manual transmission parts. Edit: Further checking reveals that only the engine and dash harnesses are transmission specific. The rear harness is the same for either transmission. So I might be able to do it with just the dash and engine harnesses from a manual transmission car.
  
• The two dash harness parts I have (24013-E4705 & 06) were apparently listed by Nissan as an assembly under 24013-E4703, listed as "ASSY-HARNESS INSTRUMENT" for automatics between 10/70 and 12/70 inclusive. This is not encouraging to me, as I fear that there won't be many possible donors (automatics in a very short 3 month period).
  
• Just in case, I called my local dealer, and the automatic harness assembly part number is no longer in their computer, and it is not listed as superseded.
  
• The matching manual transmission dash harness assembly (24013-E4702) is still a good number, but it is NLA from Nissan.
  

So it looks like I have two options - 1.) try to find the proper (but possibly rather rare) original automatic dash harness assembly, or 2.) bite the bullet and swap the whole works to a similar manual transmission harness. Number 2 is probably the more likely option, I'm guessing.

[Arne]

Here's the scoop so far. After more research, and corresponding with several possible suppliers, the two choices I listed in the last post are still accurate. Either find a replacement dash harness assembly that is the same as mine, or replace both the dash and engine harnesses together.

As I feared, the harness I have now (automatic from 10/70 to 12/70) appears to be rather hard to find period, to say nothing about finding a good unmolested one. But further thought now makes me think that might not be such a bad thing, as it tends to force me to do it 'right.'

You see, the more I think about it, the more I think I'd like to replace the engine harness anyway. I think my current engine harness is OK, but is it really? When the fusebox suffered its meltdown, it melted wires in the dash harness as well. Could it have melted wires even farther back into the engine harness? Certainly. Did it? Don't know. But I do know that my car does not have a fusible link on it right now (removed and bypassed at some time before I bought the car), and that makes me suspicious.

So I think my preference right now is to replace both of those harnesses. To ensure that everything works, what I believe I want is to keep my existing rear body harness (24014-E4601, used on all early cars up through 12/70), get a good engine harness (24012-E4601, used on manual transmission cars from 2/70 to 12/70) and a good dash harness (preferably 24013-E4602, manual from 10/70 to 12/70). I could possibly use dash assembly 24013-E4601 (from 1/70 to 9/70), but I don't know what differences that might require under the dash.

Can anyone out there think of any electrical differences between late '70 cars and the very early '71s in the dash harness area? Warning lights? Door buzzer? Something else?

Edit: I've now been told that the earlier production cars (prior to 10/70) did not come with the key-in-ignition buzzer. If true, that may well be the only difference in the dash harnesses listed above. And since I could live without the buzzer, that would open more options for me.

[Arne]

Any of you who have manual transmission 240Z's built from 2/70 through 12/70 - help!

If any of you have the dashes out of your car (so that the harness part number tags can be easily seen), I could use the numbers from both sections for both the 2/70-9/70 and the 10/70-12/70 versions. I know the assembly part numbers for both of those stretches, but most used parts suppliers want the actual sub-harness numbers instead.

[kenz240z]

It might cost a bit more, but the two sources listed below may be able to build a new harness for you.

www.painlesswiring.com

www.wire-works.com

[Arne]

I actually looked into that option. Unfortunately, those companies (and other similar ones) are geared up more for custom harnesses for hot rods and muscle cars. They don't have the OE Datsun terminals and connectors on the shelf, and since they don't have templates for our cars, they'd need a good harness to copy from. Not a very feasible option for my needs, I'm afraid.

[Arne]

The latest - Thanks to those of you out there who helped my research by finding and sending me the part numbers off of your harnesses.

At this time my plan is to purchase a complete harness from a single car, either a late '70 or early '71 with a manual transmission. Once I have the harness in my possession, I will (before I put it in the car) test the resistance on each wire, disassemble and clean all the terminals, and resolder terminals as necessary. Basically I plan to refurb the harness before I put it in the car. Time consuming and tedious, yes. But when done, it should all be good.

For reference, I will try to find a matched set of 24012-E4601 (engine harness), 24013-E4601 or E4602 (dash harness assembly) and 24014-E4601 (rear body harness). Interestingly, although the two dash harness assemblies listed above are supposed to fit different build dates (2-9/70 and 10-12/70 respectively) the sub-harnesses found in cars in both ranges have been the same in the reports I've seen so far. The sub-harnesses are 24013-E4650 & E4651.

[Arne]

It's been 5 weeks since the last post, and I don't know how much of that time I have spent fretting about wiring. I've learned several things:

1. Good Series I wiring harnesses do exist, but are not all that easy to round up.
   
2. About the only way to get a full set from a single car is if you buy your own parts car. And good luck finding a parts car with intact wiring.
   
3. Pricing for harnesses is all over the board. For the full 3 harness set, I got prices from $150 to as much as $900!

Since I couldn't easily get a full set from a single car, I decided to drop back and do it one section at a time. Since the dash harness assembly is the one that I KNOW is bad, it was the place to start.

So this morning my dash harness (24013-E4602) arrived, along with a matching long-tail fusebox. Completely intact, right down to the fuse holder for the radio. No signs of ever having been hot. The fusebox also shows no sign of getting hot. So for the rest of the weekend, I'm planning to get out the Fluke and test each wire for continuity and resistance. I'll also clean all the terminals, and make any necessary repairs before I pull the dash to install it. The same for the fusebox, a couple of the rivits seem a bit loose so that will be dealt with before it ever goes in the car.

Once this harness and fusebox is installed, I can perform some tests to decide if either the body or engine compartment harnesses are really needed. Stay tuned.

[EScanlon]

Arne:

Hoping to save you some energy, time and frustration.

MANY, and I mean MANY of the wires have multiple connections along the length of the harnesses. It may be a very frustrating experience trying to Fluke each and every wire at each and every connector.

Believe me, you will find after a few wires that you will begin to suspect that EVERY wire is cross-connected. They aren't, but they have so many cross-connecting circuits as to make a bowl of spagheti seem simple. And this is WITHOUT the instruments / switches in place.

If you were to connect the instruments / switches, then you'd MULTIPLY the complexity and not simplify your task.

Rather than test for resistance and continuity, presuming that both of the harnesses appear intact and unmolested, I would concentrate on inspecting each connector, and it's individual wire connectors for damage, corrosion, loose gripping connectors, and frayed connections.

Replace the plastic shells of any doubtful ones with donated shells from your original harness. Effect repairs on frayed connections, and tighten any loose ones. Lastly give them a good brushing with either a toothbrush soaked in a mild metal cleaner (or contact cleaner), or vinegar. Don't forget to neutralize the cleaner you use to ensure that it doesn't cause corrosion and hence problems later. Then make sure the connectors are clean and dry.

I'm not a big fan of dabbing gobs of dielectric grease in wiring harness connectors, in fact I would recommend against it. Simply put, you're not immersing the car in water, and it just adds another goopy mess to deal with as you work within the car's tight behind the dash area. Lastly, it tends to REALLY complicate troubleshooting circuits later.

Take a look at the instrument bulb sockets. Make sure those have a nice bright contact at the center post and on the ground clamp. If any of them have broken edges or clamps, then repair / replace as needed.

But the bottom line is don't waste your time in effecting tests of items that you simply cannot change without a lot of effort and hazzle that would render the whole project useless.

Checking for resistance in the wire (and it IS there) won't do anything more than to introduce doubt in your mind as to the integrity of the wiring.

Continuity checks are great....if you know exactly where EACH connection is supposed to connect to AND it's sub-connections, and can effect conductivity to all of them. Otherwise, you'll be moving, bending, jostling and pulling on a 30 year old harness filled with old wires...definitely NOT your best form of maintenance.

Get my drift?

Enrique