Series 1 240Z reverse light complications

[1971s30]

Hello,

I have a 1971 Series 1 240Z which has a few issues which needed to be rectified to pass inspection here. One of which was the reverse lights not working, which I thought would be a simple fix.

-I haven't checked the reverse switch itself yet, because there is a continuity issue with the red/black wiring ( I jumped the red to red black cables at the switch but nothing)

- I have power at the red wire to the switch.

Here is where things are confusing me. I have continuity from the red/black wire at the switch to the red/black wire at the three prong connector (shared with YG/BY) from the engine compartment harness to the dash harness. However, there are two red/black wires going to the body harness from the dash harness, neither of which have continuity through the dash harness. This is the first issue.

Second issue is the body harness itself has been subject to some serious modification. The body harness has THREE red/black wires (one of which looks like rear defroster), but the ones of the pronged connectors do not have continuity with the wiring at the reverse lights. The only wire that has continuity with the wiring at the lights is a red/black wire that has been connected to the spade going to the pass side door switch (??).

Also, the wiring going up the frame after the seat has been chopped, and been butt spliced to different colored wiring. However, at the tail end of the car, most of the wiring appears factory.

I know I could simply bypass the dash harness altogether.

My questions:

- What is the purpose of the black wire at the body harness connector? What else is going to ground from the dash harness? It appears the body harness has its own ground point.

- Is the reverse light wire going through a pronged connector on the dash harness to the body harness on Series 1 240z or is it a separate butt style connection?

- What do I do with the door switch? I never checked if it actually works. I wouldnt be too bothered if it doesnt however.

 

Thanks for your help!

 

 

[Zed Head]

There are several ground points in the harness and at various components and lights.  Have you looked at any wiring diagrams?  Your questions are very non-specific so they're hard to answer.  "What is the purpose of the black wire at the body harness connector?"  You talked about a whole of red/black wires but didn't mention a black one.  The door switch?  You could re-establish the original purpose.

Here are some resources to work from.

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

http://www.classiczcars.com/files/category/11-240z/

[1971s30]

Sorry I will be more specific.

- My first question is the exact path of the negative size of the reverse switch (red/black). It goes through three different harnesses. I do not have continuity through the dash harness. Please see attached picture. I am wondering which connector it is supposed to come through to connect to the body harness?

- Which effectively leads to, which red/black wire feeds the reverse lights in the body harness? I have three. The body harness diagram only shows two.

- I have circled the black wire at the connector in the body harness in the attached picture. The body harness seems to have its own ground and connects everything shown in the wiring diagram indicating nothing else would come from the dash harness to ground, so what is the purpose of the connection to the dash harness?

The wiring diagram for early 240zs only show the red/black wire going from the reverse switch to the reverse lights and nothing else.

[Zed Head]

I see your problem.  I just uploaded some 1971 FSM supplements that have wiring diagrams on page 34.  Not sure if it will help though.if wires have been cut.  It does show another circuit if the car is an automatic, to the inhibitor switch.

 

[1971s30]

Thanks Zed Head, I had the other illustrations but the one with the labeled butt connectors on the dash really helps. It shows two butt connectors for the backup lights, BR and BL. That could explain the lack of continuity within the dash harness itself. I saw the BL one somewhere and I'll look for the BR one. I wish I knew where the BR connection to the body harness to the reverse lights was.