No wipers, Running lights or dash lights...

[MY1PATH]

I've got a short somewhere... Ok actually found a few but not the actual problem... New motor is in with new matchbox dizzy and alternator. Old ignition box unplugged and alty wiring has been double and triple checked (and more). Car runs great and I'm excited to go places but I have a lighting issue that is keeping me off the road for obvious safety reasons.

I first noticed it on my first early morning drive when I could not see the cluster. No dash lights and no running lights. I checked all the fuses and they are fine. So checked everything the car has: Headlights, brights blower fan, brake lights, Hazards, Turn signals all work. Wipers do not. 

I've read about a few various shorts in the running light fixtures so I removed all those and inspected one by one (left them off for now). The fixtures are good, one of the insulators on a connector was missing and there were some burn marks but not the problem. I found a few unused connectors like that in various places around the car and taped the off but still not the problem. I inspected and cleaned the column switch but no luck (yes, there is power coming to the switch). I did find that bridging power to the running lights from the headlights brings them on and lights up the RH arrow in the cluster...

I am getting really burnt out on this!!! I just want the lights to work. Short of pulling up the dash and running through every shred of wire or doing a complete rewire of the car (it's coming, eventually) are there any suggestions you guys have?


1974 260z 2+2

Edited August 29, 2016 by MY1PATH

[sweatybetty]

it sounds like you just replaced the engine? did everything work before that?

[Zed Head]

A "short" will blow a fuse or fusible link or melt some wire insulation.  If you didn't find any of that then you have an open circuit.  Helps the thought process.  

I think that one fuse covers the lights you mentioned.  You might dig deeper in to the fusebox and that fuse.  The older Z's tend to melt fuse boxes and wiring around a few certain fuses.  Search SteveJ's name and get on to his "Fiddlin with Z cars" site.  I think he has some good info about it.

[SteveJ]

On your FB post, you don't give the year of your car. However, armed with the fact that I now know you have a 74, I think I may be able to help you.

You said you looked at the combo switch. Did you examine the 9-pin connector closely? On my 260Z, it was full of melty goodness so that it wouldn't make contact even when it was plugged together. Replacing the shell did the trick for me. That restored my parking lights. The wipers are on the same connector.

Take some clear photos of that 9-pin connector, both the switch side and the dash harness side. Be sure to get all four sides and where the connectors plug together. Post the photos here so we can see if that is your problem.

[MY1PATH]

1 hour ago, sweatybetty said:

it sounds like you just replaced the engine? did everything work before that?

yes, and I think it all worked for a short time after the swap too.

5 minutes ago, SteveJ said:

On your FB post, you don't give the year of your car. However, armed with the fact that I now know you have a 74, I think I may be able to help you.

You said you looked at the combo switch. Did you examine the 9-pin connector closely? On my 260Z, it was full of melty goodness so that it wouldn't make contact even when it was plugged together. Replacing the shell did the trick for me. That restored my parking lights. The wipers are on the same connector.

Take some clear photos of that 9-pin connector, both the switch side and the dash harness side. Be sure to get all four sides and where the connectors plug together. Post the photos here so we can see if that is your problem.

I have a little melty on running light corner of that connector but my multimeter tells me its still making good contact. 

51 minutes ago, Zed Head said:

A "short" will blow a fuse or fusible link or melt some wire insulation.  If you didn't find any of that then you have an open circuit.  Helps the thought process.  

I think that one fuse covers the lights you mentioned.  You might dig deeper in to the fusebox and that fuse.  The older Z's tend to melt fuse boxes and wiring around a few certain fuses.  Search SteveJ's name and get on to his "Fiddlin with Z cars" site.  I think he has some good info about it.

A full short will. A partial short or short to another device could cause excessive draw will stop all other items on the circuit from working. Fuse box appears to be in mint condition (front and back) unlike the rest of the car...

what I'm trying to figure is where do dash/running, lights wiper and rt indicator arrow have in common... the rt arrow coming on when bridged power supplied to dash...

 

 

[SteveJ]

Check your bulbs. You may have an 1156 bulb in the front or back right turn signal. The proper bulb is an 1157. An 1156 will cross paths between the parking lights and turn signals.

Otherwise, the other circuits that you mention have the combo switch and 9 pin connector in common.

[MY1PATH]

Just now, SteveJ said:

Check your bulbs. You may have an 1156 bulb in the front or back right turn signal. The proper bulb is an 1157. An 1156 will cross paths between the parking lights and turn signals.

Otherwise, the other circuits that you mention have the combo switch and 9 pin connector in common.

I'll have a closer look at the 9 pin again, maybe something bridged inside it...
All signal lights and marker lights are unplugged right now. The resistance to ground went down with each one removed, I thought I might poke my way closer to the problem once all bulbs were removed from the circuit but with no luck...

[SteveJ]

By the way, you can get a replacement connector from http://www.vintageconnections.com. I've purchased plenty of connectors from that site.

[MY1PATH]

14 hours ago, SteveJ said:

By the way, you can get a replacement connector from http://www.vintageconnections.com. I've purchased plenty of connectors from that site.

Good to know!
So all the pins in that connector probed good end to end, they all click into each other and none of them are bridging.
Definitely a short, with all the running lights and dash lights unplugged I'm still getting 5.7ohms resistance to ground on that circuit.
I started my digging this afternoon at 3ohms resistance to ground. I found some funky stuff with a power antenna in back and another set of exposed but unused running light connectors inside the rear quarters... I started peeling back panels and carpet removing all kinds of unused electrical from seat belt sensors and seat pan sensors and a mess of Amp and speaker wires from a sound system that is no longer there... 

So I'm finding lots of little things and each time my resistance to ground increases but still not found the main culprit...

[SteveJ]

Okay, let's fix some terminology here.

(As Zed described above) A short circuit is when a circuit is completed without a load (or with minuscule load). There is enough current flowing through the circuit to damage the wiring catastrophically  or activate the circuit protection (fuse or circuit breaker). You said your fuses were fine. You talk about having 5.7 Ohms resistance.  Neither indicates a short. As a matter of fact, at 5.7 Ohms, that would only be 2.1 Amps of current.  That isn't a short circuit for that circuit. You might be seeing the resistance of the dash light bulbs. You don't say what color wire you are checking or where. 

If the lights don't come on, and your fuse is good, then you have an OPEN circuit. An open circuit could be caused by a bad switch, an inadequate mechanical connection at a wiring connector, a compromised path to ground, etc.

Even if a fuse is blowing or a wire is showing signs of overheating, it doesn't necessarily mean you have a short circuit. You could have a cross connection (too many parallel paths for current flow). Those can be a pain to diagnose.

At this point, you have a choice to make. Zed and I both have plenty of experience doing electrical diagnostics. @beermanpete is excellent, too. We could guide you through diagnosing the wiring, or you can continue to proceed in a haphazard manner.

In order to do the former, you will need to help us. When we make a request, it is not done to waste your time. It is to help us to know what is the condition of the wiring. 

I asked you early on to post photos of a specific connector. It is because I have have see issues in that area on more than one car. If nothing else, it would help eliminate that as a cause for the issue on your car.

[MY1PATH]

12 hours ago, SteveJ said:

Okay, let's fix some terminology here.

(As Zed described above) A short circuit is when a circuit is completed without a load (or with minuscule load). There is enough current flowing through the circuit to damage the wiring catastrophically  or activate the circuit protection (fuse or circuit breaker). You said your fuses were fine. You talk about having 5.7 Ohms resistance.  Neither indicates a short. As a matter of fact, at 5.7 Ohms, that would only be 2.1 Amps of current.  That isn't a short circuit for that circuit. You might be seeing the resistance of the dash light bulbs. You don't say what color wire you are checking or where. 

-Sorry, the green white wire that goes to the running light circuit and as stated above all lights (including dash lights) are disconnected when this measurement is taken.

If the lights don't come on, and your fuse is good, then you have an OPEN circuit. An open circuit could be caused by a bad switch, an inadequate mechanical connection at a wiring connector, a compromised path to ground, etc.

Even if a fuse is blowing or a wire is showing signs of overheating, it doesn't necessarily mean you have a short circuit. You could have a cross connection (too many parallel paths for current flow). Those can be a pain to diagnose.

-The switch works, tested both at the solder joints on the switch and at the connector. Ok, I get it, short is the wrong word. Crossed connection as you describe seems to be exactly my situation.

At this point, you have a choice to make. Zed and I both have plenty of experience doing electrical diagnostics. @beermanpete is excellent, too. We could guide you through diagnosing the wiring, or you can continue to proceed in a haphazard manner.

-Haphazard, perhaps but it was not without findings and all those unused wires were going to be removed sooner or later.

In order to do the former, you will need to help us. When we make a request, it is not done to waste your time. It is to help us to know what is the condition of the wiring. 

I asked you early on to post photos of a specific connector. It is because I have have see issues in that area on more than one car. If nothing else, it would help eliminate that as a cause for the issue on your car.

-Ok replies are typed in inline with your quoted text. It was easier for me to compose it that way. And here are the pictures you requested. Thankyou, I don't mean to come off as ungrateful. 

[SteveJ]

Thank you. That helps. Yes, the parking light circuit was/is overloaded. The connector overheated. It may not be making good contact at that pin anymore. Mine was worse.

Check your side marker sockets and right side turn signal light sockets. One or more could have corrosion between the housing and the center pin where the positive is. That gives another path for current to flow. Take some photos of the side markers (with the bulb pulled) and the right side turn signals. You may have corrosion in the right front turn signal. That would account for the turn signal indicator lighting up in your previous experiment, that is if you didn't already discover an 1156 bulb in that socket.