Wiring woes

[72 SBC 240Z]

1972 SBC 4bbl/TH350

 

No electric after market anything except for electric fan and water temp gauge

 

There is a lot of weird wiring behind the dash that the previous owner did that makes no sense to me, it's apparent that they cut/spliced/cut again/spliced again/ several times but it doesn't go anywhere, it just ends so whatever they had in the car is gone.

 

Okay now that's out of the way, I'm finally in reach of being able to drive my z the windshield I've been waiting for several months now is due to be installed tomorrow but after doing some cleaning up on the car I find that the headlights, blinkers, hazards and brake lights are not working all of the sudden. The car has been in my garage for over a year now waiting to be driven but I checked the lights just a couple days ago.

 

I pulled the dash the other day and reinstalled it, making sure all connections are good but Im at a loss here and have been studying wiring schematics all evening.

 

I have a blue wire near the fuse panel with an inline fuse that as soon as I turn the key to on it blows so obviously it's grounded out somewhere but the only blue wire with an inline fuse in the wiring diagrams leads to "cooler" what is that?

 

My side marker lights, tail lights, gauge lights work fine, but the headlights (low and high beam), blinkers, hazards and brake lights are doing nothing

 

My only guess is that some of the PO's funny wiring left a loose hot wire that's grounded out somewhere in the dash?

Edited October 3, 2011 by 72 SBC 240Z

[Dershum]

For the blinkers/brake lights/etc., I would check your hazard light switch. If it's anything like my 71, a bad switch there (or an incorrectly wired one) will take all of those out. They all run through that switch so that they can come on when you turn on your hazard flashers.

 

For the headlights, I had a similar problem. First, go back to the wiring where they connect to the combo switch on the steering column. I would bet that you simply have two of them crossed, assuming they were working previously. If not, try turning them on and seeing if you have any current downstream from the switch. You can do it right at the headlight socket if you want, but if you're reading some voltage, but not a full 12+, then I would suggest cleaning the contacts on your headlight switch. It's pretty easy, but if those contacts are corroded (mine were) and you're not getting a full 12+ (around 12.3-12.4 with the engine off) then I would bet that's where your problem is.

 

FInally, I would strongly suggest the fuse box upgrade that MSA sells. It's an extremely worthwhile investment, and once you get everything sorted out, it'll give you gerat peace of mind knowing you're not running the older fuse box that tends to melt...at least if it's like the one that was on my 71.

[72 SBC 240Z]

Thanks for the reply Dershum, I would love to upgrade to the newer fuse box, I've eye balled it several times on MSA but unfortunately money is tight right now and MSA is pretty proud of their products. I'd definitely be sure to check the hazard switch but would an unconnected hazard switch really keep the brake lights from working too? After studying the wiring schematic for a couple hours last night it's become apparent that Nissan wiring these things up in a very "interesting way". I've always owned Z's but never a first gen before and man this thing is different plus it doesn't help that I've been DD'ing an S13 for the past couple years and really got used to hwo everything worked on it.

 

It still amazes me that a carbureted 40 year old car can give me so much trouble.

 

I know my first post was a bit rambly after working the entire weekend to get this car road ready today but to recap in a simpler way

 

All lights were working fine

saturday- pulled dash out and reinstalled all lights (not 100% about brake lights, didn't check) were still working

sunday- cleaned up interior and found that headlights, brake lights, blinkers and hazards aren't working but tail lights, side markers and gauge lights are working fine.

 

So, on my to do list today is

 

1) verify power at the headlight plug, if not check all fuses, connections and switch

2) inspect hazard switch (would a faulty turn signal switch have the same effect?)

3) lay down in that oh so comfortable position where I can stick my head up in the dash with a flashlight in my mouth while I check all the wiring connections

4) pray I don't have to pull the dash again.

 

It seems to me that the blue wire with the inline fuse behind the fuse box goes to the blower motor or something of that sort so I'm not too worried about it, in fact I think it's been blown the entire time I've had the car so I'm not too worried about it having anything to do with the lights but while I'm check under the dash I'll look for any wires that may be grounding out on something metal.

[72 SBC 240Z]

Okay let me take that back it appears the blue wire with inline fuse could be for the wipers or something to do with the radio, my guess would be wipers since now that I think about it they don't work.

 

 

Edit: Dershum you really seem to be onto something, after a bunch of search it seems like a bunch of people have had the same problem and it was either the turn signal switch or the hazard switch, i well definitely be paying both of them close attention when I work on her today. I will probably add to my to do list removing both switches from the steering column and cleaning up their contacts.

Edited October 3, 2011 by 72 SBC 240Z

[Tony D]

My SOP is to pull out all P.O. wiring. Restore all wiring to it's proper factory location per FSM and Schematic...and know what? It's worked flawlessly EVERY time!

 

My first step would be to REMOVE ANYTHING NOT STOCK. It can only cause problems. If there isn't an OBVIOUS function to a wire ADDED to a system which worked when new...(like a burned wire that is clipped and lagged) remove it, you don't need it.

 

As for Hazard Switch---that kills your blinkers for sure (hazard AND turn signals.)

 

Headlights---for that matter most lights: Common Big Ground Wire under the steering column. Easily disconnected and many seemingly unrelated things won't work unless it's connected.

 

After that, bulbs, bad local grounds, etc...

 

But my guess would be the above fixes most all of it.

[72 SBC 240Z]

Okay Update: Problem Solved

 

I started off checking the steering column first, at first glance everything looked fine but I started digging in the mass of wires and found a bullet connector and spade connector hiding amongst it all that weren't connected, I hooked them up and nothing happened so I starting checking the other wiring until I worked my way over to the fuse box, once again amongst all the wiring I found two spade connectors one male and female hiding and when I connected them together the hazards, brake lights, and headlights started working.

 

I still do not have blinkers but I have not touched the blinker switch yet so I'm betting that a good cleaning will take care of that. I also don't have wipers but if I listen closely I can hear the motor make a noise when I turn it between off and on so I assume there's a bad connection or seized motor, temporary solution= rain x and/or don't drive in rain.

 

headlights working (low and high beam)

hazards working

brake lights working

 

only thing left is blinkers, wipers and the fuel gauge

 

I have singled out that the wire with inline fuse that blows as soon as i turn the key to the "on" position is most likely the blower motor since it's the only thing left not working.

 

I appreciate the help guys

[Dershum]

Glad you got some of it worked out...small victories keep you going

 

I'll 110% second Tony D on his statement. I've torn just about every bit of PO wiring out of the car, with the exception of a very strangely wired headlight harness that I still haven't fully sorted out. As a matter or fact, this past weekend I was reinstalling my newly upholstered seats, and decided to tackle a really bizarre wire that was running along the driver side doorsill. Turns out that it was a connection from the front blinkers to the rear ones, but two of the three lines were taped off, only connecting a power lead. I'm still not 100% sure it's correct, but I at least pulled out a bunch of the extra/strange wires, ran it along the tunnel so it wasn't somewhere I could catch my foot on it. Also, there was some sort of aftermarket switch that appeared to have been spliced in to raise the antenna. I'm not sure what is "correct" as far as the antenna (the original radio is long gone) but something tells me it wasn't original...and I don't have a radio anyway, so out it came.

 

As for what you have left, I have a non-functional fuel gauge as well. Goes to "F" no matter what's in the tank. I just haven't gotten around to diagnosing it yet. I just try to make sure I keep gas in it

[72 SBC 240Z]

My fuel gauge sits below E, I'm not sure how much fuel is in the car but I know it's nowhere near full. Maybe if the tank hasn't got much fuel in it, it just drops to E, I dunno I'll just fill it up for now.

 

I was cleaning up the wiring in front of the radiator with loom and electrical tape, all my lights work but I have about six or seven factory looking wires that they clipped, I have no idea what they go to, I can assume two are for the horns but I don't have any horns anyway, that leaves five wires with no idea where they go.

 

Thanks for the help guys, I'm pretty stoked because my windshielf finally came yesterday and got installed, I have most of my lights back, and I'm only left with trying to adjust my float levels on the holley and replacing a tranny gasket then I should FINALLY be road ready.

[72 SBC 240Z]

Reached through the glove box and jiggled the wiring on the back of the fuel gauge and it started working haha! Still no blinkers though but haven't tried messing with it, was too busy messing with the holley.

[72 SBC 240Z]

Why does half the internet say there are two flasher relays for the 240z and the other half of the internet say that there is only one?

 

Dismantled my turn signal and headlight/wiper switch today. I cleaned the contacts and reassembled, lights are working good but still no wipers or turn signals. In the process I touched the horn button the wrong way and it just broke off, everything in the world is trying to keep me from getting to the DMV!

 

I guess I will spend tonight looking at wiring schematics again, I wish I could find one that was laid out how the wires actually are in the car. I have three green wires dangling to the left of the steering column, one of them is hot while the key is on. Next to the flasher unit on the right side of the car I have two wires coming together to one spade connector.

 

Current status:

 

No reverse lights (not worried about it)

No turn signals (bad idea to go without these in florida)

No tachometer (have not tried the 10k ohm resistor for the tach signal wire yet)

 

 

Edit: The blue wire with inline fuse that blows as soon as i turn the key is not going to the blower motor apparently, the blower motor started working randomly. It's quiet and blows good, must not be orginal!

Edited October 5, 2011 by 72 SBC 240Z

[72 SBC 240Z]

UPDATE: Okay, I'm going to use the excuse that I've had a mental block up until this point to excuse me not figuring this out sooner. Rather, putting 2 and 2 together sooner.

 

Okay so over the weekend I did all the work I mentioned above right? One of those things involved me installing a new electric water temperature gauge. In order to do this I needed a 12V source, amongst the mess of the previous owners wiring I found a loose dangling wire that had power whenever the key was on. I figured what the hell it isn't hooked up to anything so I used that as my power source. Today I noticed that while I was probing around with my test light that if I turned the hazards on while the key was in the on position my temp gauge would lose power.

 

So, putting two and two together here, I have no flasher relay near my steering column so that means it's not there right, obviously, I have several wires that may or may not go to that but if I have one particular wire that has it's power cut when the hazards are on that would be the wire for the turn signals right? Since the hazards override the turn signals.

 

Now, my question is does this 12V source go directly to the flasher unit or does it go elsewhere? I'm having no luck finding a decent wiring schematic. This is when it pays to have a spare car to go look at.

[ktm]

I have singled out that the wire with inline fuse that blows as soon as i turn the key to the "on" position is most likely the blower motor since it's the only thing left not working.

 

Editted for posterity. I was mistaken. I was thinking of the solid green wire. The blue wire is for the defroster as Beermanpete correctly stated.

Edited October 6, 2011 by ktm

[rossman]

I'm having no luck finding a decent wiring schematic.

 

Have you looked at the FSM wiring diagram?

[72 SBC 240Z]

Rossman, Yeah, I've looked at several different versions of wiring schematics that all say the same thing with a different layout. I guess it's because of the previous owners butch job of certain wires that's left me confused, I'm down to just a few mystery wires and I think I have those sorted out, I will report back tomorrow.

 

KTM, if that's the case then I'm okay with that since I'm running a mechanical pump

[beermanpete]

...

 

Edit: The blue wire with inline fuse that blows as soon as i turn the key is not going to the blower motor apparently, the blower motor started working randomly. It's quiet and blows good, must not be orginal!

 

The blue wire with in-line fuse is for the rear window defroster.

BE Body Electrical.pdf

[Dershum]

everything in the world is trying to keep me from getting to the DMV!

 

What's the rush to get to the DMV? Inspection? Do they have historic-style plates in FL? Cause in NJ with Historic plates I don't believe you need an inspection...at least from everything I've read its not required, and I don't even have an inspection sticker on my Z any more (with historic plates) and haven't gotten much more than a wave from the local cops.

[72 SBC 240Z]

Because the car was previously titled in another state they have to visibly verify the vin number on the title matches the car. I'm in a rush because I want to drive this car. I mean for all intents and purposes I believe her to be road worthy but as soon as I'm ready to get to the DMV something else pops up. Don't get me wrong though, I'm glad these little things are coming up now rather than in the middle of traffic. It's just hard to set aside time to get to the DMV, I recently went back to school so I'm in class mon-fri 7-12 and then 5:30-7:30pm and in that time between classes I'm usually working to make a piddly amount of money to get by on.

 

I have been working on this car for a long damn time now and it really doesn't show to me, the car has come a long way but to the common passerby it looks like I just threw it together compared to a lot of other nicer projects.

 

Okay! on to the wiring update

 

Yesterday I picked up a flasher unit, located the solid green and white wires above the steering column and the blinkers were working except for the passenger side rear, the bulbs look fine and both the tail lights and brake lights work so there must be something interupting the signal. But then randomly the turn signals stop working as did my fuel gauge, I don't know if these things are related though, they seemed to happen at the same time. I didn't change or touch anything, they just stopped working, there is no power going to the green wire now, all fuses in the panel checked out, and the inline fuse (not the blue one that keeps blowing) behind the fuse panel is checking out okay. Are there any other inline fuses hiding somewhere related to the turn signals.

 

Parking lights, head lights, gauge lights, hazards and high beams are all still working

 

thanks again for all the help guys!

[beermanpete]

snip...

 

Yesterday I picked up a flasher unit, located the solid green and white wires above the steering column and the blinkers were working except for the passenger side rear, the bulbs look fine and both the tail lights and brake lights work so there must be something interupting the signal. But then randomly the turn signals stop working as did my fuel gauge, I don't know if these things are related though, they seemed to happen at the same time. I didn't change or touch anything, they just stopped working, there is no power going to the green wire now, all fuses in the panel checked out, and the inline fuse (not the blue one that keeps blowing) behind the fuse panel is checking out okay. Are there any other inline fuses hiding somewhere related to the turn signals.

 

Parking lights, head lights, gauge lights, hazards and high beams are all still working

 

thanks again for all the help guys!

 

It sounds like the turn signal (T/S) section of the combination switch. The brake light circuit and T/S circuit both go through the T/S switch and use the same wiring and bulbs after the T/S switch. If it is not the actual T/S switch contacts it is the wiring connectors that connect the T/S switch to the wiring harness under the steering column.

 

Another thing to check is the brake lights while using the turn signal. I have seen a few cases were the brake light on the side opposite the side flashing goes out due to dirty/worn T/S switch contacts.

[Dershum]

Because the car was previously titled in another state they have to visibly verify the vin number on the title matches the car. I'm in a rush because I want to drive this car. I mean for all intents and purposes I believe her to be road worthy but as soon as I'm ready to get to the DMV something else pops up. Don't get me wrong though, I'm glad these little things are coming up now rather than in the middle of traffic. It's just hard to set aside time to get to the DMV, I recently went back to school so I'm in class mon-fri 7-12 and then 5:30-7:30pm and in that time between classes I'm usually working to make a piddly amount of money to get by on.

 

I have been working on this car for a long damn time now and it really doesn't show to me, the car has come a long way but to the common passerby it looks like I just threw it together compared to a lot of other nicer projects.

 

Okay! on to the wiring update

 

Yesterday I picked up a flasher unit, located the solid green and white wires above the steering column and the blinkers were working except for the passenger side rear, the bulbs look fine and both the tail lights and brake lights work so there must be something interupting the signal. But then randomly the turn signals stop working as did my fuel gauge, I don't know if these things are related though, they seemed to happen at the same time. I didn't change or touch anything, they just stopped working, there is no power going to the green wire now, all fuses in the panel checked out, and the inline fuse (not the blue one that keeps blowing) behind the fuse panel is checking out okay. Are there any other inline fuses hiding somewhere related to the turn signals.

 

Parking lights, head lights, gauge lights, hazards and high beams are all still working

 

thanks again for all the help guys!

 

Sorry, didn't meant to be accusatory or abrupt, I was just hoping it wasn't for inspection purposes and hoping that FL had something similar to NJ. Glad to hear things are working out though!

[72 SBC 240Z]

Nah man all is good, I was just stating that I'm glad that Florida doesn't do any kind of vehicle inspection because not a single car I have ever owned would pass with the exception of my 98 328IS, maybe. . .

 

Gentlemen I know this is off topic of my own thread but today I drove the car from my coworkers house where I've been storing it while I've been working on it. Having it there is the main reason I've been having trouble diagnosing my wiring problems because I can only physically check all of your different suggestions whenever I was over there working on her, that's why I spent so much time in the evenings studying wiring diagrams and whatnot, so that when I went over there the next day I had some fresh ammo. Any who, back to what I was saying, I drove the car from across town where it was to the DMV nearest my new home and got her all legal to drive. Just to point out how little Florida cares, I have no side mirrors, no wipers, no bumpers, and that's just what she could see on the outside but all she was doing was checking the VINs.

 

It was awesome to finally get to drive her, with the exception of the 5 minute test drive around the block I did a few days ago this is the first time I have ever got to drive the car in the two years I have owned it. I know this isn't the V8 section but even with that chunk of iron up front she handled great, the brakes were smooth, she even drove in a straight line on her own! The steering wheel moves a little more than it should but I wouldn't be surprised if a good greasing doesn't take care of that.

 

Without HybridZ I don't think I would have been able to make it this far without losing my mind, I know a carb'd motor swap is about the simplest thing you can do but all those little buggers that come with a 40 year old car can drive you nuts.

 

P.S. my fuel gauge and blinkers work intermittently, evidently there's a loose connection somewhere.