Help: 71 240z Dash Wiring, no start or lights.

[spitsnaugle]

My dash is out and I'm trying to get the car started to get it from my friends place to my home. No gauges or anything are installed, just the harness and relays.

I'll try to be as thorough as possible in explaining the situation:

 

Issue: Car has 13v power at fuse box and at key, if I turn key to on, or turn lights on, power drops to .2v ...Lights do not work, no starter clicking, no flashers or anything. It all used to work though.

Backstory:

 

It has a MSA fusebox installed by P/O. Unsure if installation is correct. two white/red wires are coming in and connecting to right side screw post. Two single (white and blue?) wires are connected from one side to the other on the fuse box.

 

It had a old cheap alarm installed. I removed this alarm, and re-connected the black/yellow wire that was spliced for it.

 

Its main ground wire had melted. I replaced the entire wire from end to end, following its connections.

 

The ignition/key has two black single wires coming off of it, are these for ground? I am unsure.

 

 

 

 

 

I am unsure if this is OEM or not, but these Yellow, Yellow/Red, Red/Blue, and Green, wires seem to run together, is this correct? I believe the yellow wires have something to do with the gauges?

 

 

 

 

 

 

 

 

 

 

 

 

 

Also, I have a few unknown issues that may be related or not:

I have this copper&plastic piece coming from the turn signal switch:

 

 

 

 

 

 

Thanks for your time.

If all else fails I'll be posting a Wanted thread for a 71 dash harness soon :/

Edited March 17, 2011 by spitsnaugle

[z2go]

Holy crap. Well, one easy fix is that last picture... that is the piece that connects the horn button to the horn relay wiring... it mounts on the left side of the turn signal switch, facing in toward the driver, and the little round contact point is spring loaded toward the steering coupler, so that it can maintain a contact and allow a connection to the horn. Make sense?

 

For the other stuff... I would advise replacing a lot of your wiring. Also, I would recommend studying the Factory Service Manual Wiring section, including the dash wiring, and especially the whole wiring diagram for the car. Once you know it by heart and can identify what every wire does, only then should you really start hacking away at the harness. There is a lot of stuff previous owners have done that is not in the FSM, and you are going to have a hell of a time figuring it out. Also, it sounds like you probably have some corroded connectors somewhere, if you are only getting .2V off the key. I would start at the ignition switch, and work my way from there, cleaning all connectors, using some dielectric grease to ensure a good contact, and checking them, one by one... until you die of old age.

 

Seriously though, this is a huge project to tackle without having a good knowledge base of what is going on with everything, being able to identify every wire, etc.

[spitsnaugle]

Holy crap. Well, one easy fix is that last picture... that is the piece that connects the horn button to the horn relay wiring... it mounts on the left side of the turn signal switch, facing in toward the driver, and the little round contact point is spring loaded toward the steering coupler, so that it can maintain a contact and allow a connection to the horn. Make sense?

 

For the other stuff... I would advise replacing a lot of your wiring. Also, I would recommend studying the Factory Service Manual Wiring section, including the dash wiring, and especially the whole wiring diagram for the car. Once you know it by heart and can identify what every wire does, only then should you really start hacking away at the harness. There is a lot of stuff previous owners have done that is not in the FSM, and you are going to have a hell of a time figuring it out. Also, it sounds like you probably have some corroded connectors somewhere, if you are only getting .2V off the key. I would start at the ignition switch, and work my way from there, cleaning all connectors, using some dielectric grease to ensure a good contact, and checking them, one by one... until you die of old age.

 

Seriously though, this is a huge project to tackle without having a good knowledge base of what is going on with everything, being able to identify every wire, etc.

 

 

Makes sense. the previous owner had ran a single white wire from the horn to the under side of the dash, it never connected to anything though. :/

 

I've been studying a couple wiring diagrams that are titled "early 240z" its got me what I thought was a decent understanding. (I am starting to see I'm a bit far from having that understanding actually)

Edited March 17, 2011 by spitsnaugle

[z2go]

Use this website to download the Factory Service Manual:

 

http://www.xenons30.com/reference.html

 

The wiring diagram should give you a better idea of what you have going on. There are some subtle differences that will be confusing if you don't have the right year, such as wire colors. Also, the colors after the harness might be a different color, and not listed on the diagram. So, your best reference point is on the harness side of the connections.

 

*EDIT*

Yours is a 71, it's not available on there... but the 72 will be close. Your dealer should be able to supply you with a 71 FSM, if need be.

Edited March 17, 2011 by z2go

[kamikaZeS30]

It has no gauges in it at all?

 

If the information I have read in other subforums here on HybridZ is correct, the Ammeter is kind of a central power distribution point in the harness. It is also kind of illustrated that way in the FSM, they call them "leads" but if you look at what goes from the voltage regulator to the dash harness, it looks more like a primary source than a lead. The White/Red wires are your positive power leads and the all White wires are your negative leads, they should be larger than the other wires (they're like 10 or 8 gauge I believe).

[spitsnaugle]

It has no gauges in it at all?

 

If the information I have read in other subforums here on HybridZ is correct, the Ammeter is kind of a central power distribution point in the harness. It is also kind of illustrated that way in the FSM, they call them "leads" but if you look at what goes from the voltage regulator to the dash harness, it looks more like a primary source than a lead. The White/Red wires are your positive power leads and the all White wires are your negative leads, they should be larger than the other wires (they're like 10 or 8 gauge I believe).

 

 

 

Thanks for the heads up, I'll put the ammeter in next time I try.

I also realized I wasnt grounding the accessory relay, it was laying on the bare floor, but I doubt it was well grounded.

I accidentally laid the red/white wires on the bare metal floor for a brief second, it didnt spark/short or anything, has me thinking that the battery isnt grounded well to the body. IDK.

 

 

[kamikaZeS30]

I accidentally laid the red/white wires on the bare metal floor for a brief second, it didnt spark/short or anything, has me thinking that the battery isnt grounded well to the body. IDK.

 

Yeah, grounding wasn't great from the factory to begin with, then when the wires are 30+ years old and resistance becomes a factor, it becomes piss-poor. I'm doing a star-ground (in the near future) for mine, but really a good braided copper strap (like something you'd find in an old GM or Chrysler) running between battery negative, the body and the engine block is enough to get the headlights working properly and start the car on the regular.

[spitsnaugle]

update:

 

 

Installed ammeter and replaced negative terminal, re-ran the wire that grounds battery to the firewall.

...and it started right up.

 

Headlights and turn signals aren't working yet, parking lights and tail lights are working though.

 

Its getting there... slowly.

Edited March 21, 2011 by spitsnaugle

[kamikaZeS30]

From those pictures you posted, your dash harness does not look like it's in need of replacement, all of the insulation looks intact.

 

Those yellow wires look like they're for sending units (oil press., water temp [i think temp is only one wire it's like white/yellow or something] and fuel level), and the blue wires are for lighting of one sort or another (headlamps, dash/gauge lights) and the greens are for indicators and controls (HVS, turn signal indicators, etc.) at least that was the color scheme on my 1/1971 Z, if I recall correctly.

Edited March 23, 2011 by kamikaZeS30

[spitsnaugle]

From those pictures you posted, your dash harness does not look like it's in need of replacement, all of the insulation looks intact.

 

Those yellow wires look like they're for sending units (oil press., water temp [i think temp is only one wire it's like white/yellow or something] and fuel level), and the blue wires are for lighting of one sort or another (headlamps, dash/gauge lights) and the greens are for indicators and controls (HVS, turn signal indicators, etc.) at least that was the color scheme on my 1/1971 Z, if I recall correctly.

 

 

It appears the yellow/red wires are power to the gauges, solid yellow and yellow/white seems to be from the sending units.

Green for the most part runs indicators and hazard switch, but solid green is at the fuse box and at the tach, it also appears to run to the hazard switch,

 

 

Here is the wiring diagram I've been using, I've been coloring it bit by bit trying to make it a bit easier to follow. I wish I had it in better quality.

 

 

(should note WR white/red striped color is switched because white on white is hard to see)

Edited March 23, 2011 by spitsnaugle