Quick question for you.

I can't seem to find a wiring diagram that includes the coolant temp sensor & thermotime switch wiring colors in the FSM.  The thermotime & coolant temp sensor (temp sensor for the ECU, not the temp gauge) each have a bullet-style to standard EFI connector harness (one harness has green wires and the other has black).

Do you guys happen to know which harness connects to the coolant temp sensor and which goes to the thermotime?  

 

-chase

You could check continuity back to the ECU connector.  That's always a good idea anyway.

On the main EFI harness, the black wires go to the temp sensor and the green ones go to the thermotime. ON THE MAIN HARNESS.

As for the little stub harnesses that connect to the main harness and convert from bullet to EFI style connectors, I'm not positive of the wire colors*. One wiring diagram I have indicates that those same wire colors were continued all the way to the thermostat housing (pair of blacks to the temp sensor and pair of greens to the thermotime), but another FSM diagram I have indicates everything past the bullet connectors is black.

So as for the stubs... I'm not so sure. But of course, since they're just a foot long, you can easily verify the connections just by tracing the stubs back to the main harness.

* And I can't check my 77 as my stubs have been remade and aren't original colors anymore.

I'm not trolling you, but "B" is black, and "G" is green.  The wiring diagrams are in the downloads section.  Resources>Downloads>Wiring Diagrams.

https://www.classiczcars.com/files/category/1-wiring-diagrams/

 

I took another look just to make sure I saw what I saw... Here's a snippet from another FSM. Supposedly for a 77.

"B" is black and "G" is green:

Edited August 29, 20204 yr by Captain Obvious

I was just pointing out to CIC that the colors are there in the wiring diagrams.  Including the main harness.

Just offering a fishing pole instead of a fish.  For future work...

I was going through the FSM and couldn't find that.  What page was that on?

(Thanks everyone btw)

It is in the wiring diagram. You can find it here in Resources - downloads - wiring diagrams. 

The FSM in section EF - Engine fuel only shows the ECU terminal numbers for diagnostics. The diagrams start from page EF-24 and show the different tests in that section of the FSM.

Edited August 29, 20204 yr by EuroDat

And the point of the snippet I posted is to show the inconclusiveness of the wire colors on the sensor side of the little stub harnesses.

The pic Zed Head posted has black for everything in those little harnesses, but the one I posted has black for one sensor and green for the other. That's why I was saying the colors on the main harness seem to be well defined, but on the sensor side, those little foot long harness extensions are ambiguous.

5 minutes ago, Captain Obvious said:

And the point of the snippet I posted is to show the inconclusiveness of the wire colors on the sensor side of the little stub harnesses.

The pic Zed Head posted has black for everything in those little harnesses, but the one I posted has black for one sensor and green for the other. That's why I was saying the colors on the main harness seem to be well defined, but on the sensor side, those little foot long harness extensions are ambiguous.

That's why I tell people to find the wire colors on the dash harness, engine harness, or body harness side of the connectors. I have seen/heard of many components using wire colors that don't match the main harnesses. Aftermarket voltage regulators come to mind.

And to add to the confussion this is the genuine replacement harness from Nissan with P/N: 24079-U8700. It is actually for the later model 79-81 280ZX iirc.

280Z Original p/n was 24079 N4202 and 24079 N4203

1 hour ago, EuroDat said:

And to add to the confussion this is the genuine replacement harness from Nissan with P/N: 24079-U8700. It is actually for the later model 79-81 280ZX iirc.

280Z Original p/n was 24079 N4202 and 24079 N4203

Yeah, those are what are on my car.  It makes sense that the sub harness and sensor connectors have matching colors.  That said - if the bullet connectors are flip-flopped in the main harness, suddenly that little trick's helpfulness goes out the window haha.

@SteveJ Yeah, that's what I ended up doing - checking the main harness wire colors then just following the wire to the plug rather than looking at the sub-harness wire colors