Fuse link wire identification

[Gillez260ZT]

Hi everyone,

I own a Hybrid 260Z (with a 280ZX turbo powertrain) with some issues that I'm trying to clear up.  I believe the electrical harnesses are a mix of 260Z, 280Z and maybe 280zx so I can't look in a service manual to figure things out (I do have all 3 manuals though).  I need to understand what's going on, and I need some help with this. 

There are a few issues I want to resolve, so I'm taking a baby steps approach, a little at a time to avoid being discouraged by the whole thing.

First step, replacing the fuse links with some Maxi fuses.  I'm not sure the wires that were in the fuse link holders were fuse links, so I'm replacing them with something cleaner looking and newer.

I've read up on a few posts online about such a replacement.  From my understanding, the fuse links were fed by 4 white wires, while the white with a red striped wires go on to other circuits after the fusible links.

The white wires have been replaced by a 4 gauge cable going from my + battery terminal to my starter, then feeding into my maxi fuse holder.

I have the 4 white with a red stripe wires to connect.  The first one splits into 2, with one wire seemingly going through the firewall toward the fuse panel on the passenger side.  The other splits into 2 again, with one wire going to the alternator on a T-shaped connector and the other to the alternator output.  Doest this make sense?  The gauge seems awful small, especially for the alternator output.

Thanks in advance for helping me figure things out, one wire at a time if necessary.

Gilles Lajoie

 

 

 

[Captain Obvious]

Gilles,

The 260 and 75 280 only had one fusible link block with two fusible links under the cover. So if you've got two blocks (with four links total under two covers), then you're engine bay harness is from a 76, 77, or 78 280Z. If you have an internally regulated alternator, you might have a harness from 78.

So, assuming you're working with a 76 or later 280Z engine bay harness with two link blocks and a total of four links, then yes... The white wire side of all four links are all connected together inside the wiring harness. Those four white wires are all crimped together inside the harness and become one white wire which attaches to the starter lug (which in turn is connected to the (+) battery cable.

The other side of those four links were White/Red, and went off to their respective destinations.

So other than a mish-mosh of different years in your 260, things do make sense.

Did you have other questions about where those four W/R wires went after the fusible links?

[Gillez260ZT]

Thanks for your reply Captain Obvious.  I'm glad the circuit up to the fuse links makes sense.  I would very much like to know where each of the four W/R wires go after the fusible links.

 

[Captain Obvious]

Glad to help. But before we start talking specifics of where the W/R side of the links go, I would like to try to identify what year your engine bay harness came from. Here are a couple questions that should help figure that out.

1) Do you have a blue wire going to your alternator?

2) How many wires do you have going to the oil pressure sensor? One or two?

3) If there is just one wire going to the oil pressure sensor, what color is it? Green, or Yellow/Black?

[tamo3]

this schematic might help you identify the line.

 

[Gillez260ZT]

Captain Obvious,  I do have a blue wire going to my alternator.  It connects via a connector in which there is also a white wire with a red stripe.

I have 2 wires going to my oil pressure sensor, one yellow with a dark stripe, the other black.  This might be aftermarket because my oil pressure is displayed via an additional gauge rather than the factory one.

Thanks for the link TAMO3, I'll take some time over the weekend to do some reading.

[Captain Obvious]

Gilles, Based on the description of the wiring, I believe your engine bay harness is from 1978.

So, there are four fusible links. The first one you have already identified as splitting into two and one side going to the alternator, and the other side going inside the passenger compartment and connecting to the fuse block. It should also split inside the passenger compartment and go to the ignition relay.

That first fusible link is the largest of the four.

The other three fusible links are the same size and smaller than the one to the alternator. The remaining three all go through the firewall into the passenger compartment and go to:

2) The multi-function stalk to power the headlights.
3) The ignition switch to power things controlled by key rotation.
4) The ignition relay (there should be two large W/R wires feeding the two halves of the ignition relay).

Is that the kind of information you are looking for?

[Gillez260ZT]

Thanks again Captain Obvious, that's exactly the info I was hoping to find.

Do any of those 3 other wires go through the fuse box before going to the combination switch, ignition switch and ignition relay?

[Captain Obvious]

No. The only one that goes directly to the fuse box is the same one that goes to the alternator.

The one that goes to the multi-function stalk goes to the fusebox after the switch.
The two that go to the ignition relay go to the fusebox after the relay.
The one that goes to the ignition switch and powers some stuff after the switch does not go to the fusebox at all (which I consider a design flaw).

For example, the starter solenoid has no fuse in the line at all. Neither does the ignition module or coil.

Now that we have identified the wiring harness year (probably? hopefully?) you can download that year wiring diagram and take a look.

Here's a mostly finished color wiring diagram for 78:
http://www.classiczcars.com/applications/core/interface/file/attachment.php?id=41454

[L2877280z]

Captain obvious, should all 4 w/r wires have power with the ignition off? Had no power to the alternator and unwrapped the harness and found this where the loom comes down from the fusible links. the verticle wire in the pic goes to the alternator. The other 3 come out of the wiring loom. Only one of those 3 has power when i check with a test light

[Patcon]

@Captain Obvious

[SteveJ]

If good fusible links are installed, all 4 white/red wires should have voltage to ground. The white/red coming off the black fusible link (assuming the links were installed in the right locations) branches off with one going to the alternator and the other branches off again with one leg going to the voltage regulator and the other going to connector C9 in the wiring diagram. The picture is zoomed in so close that I can't tell where in the loom you might be looking.