280z turn signal issue

[Premo34]

Thanks Captain. The first part of your response completely clears up any confusion and is consistent with all of my wiring. I'll start testing connections from the hazard up to the connector in the picture. My batter is strong so I can eliminate it. One thing i should add is that i was taking the 10.27 reading while the car was off and key in ON position.

I thought my hazard switch was good too. When the hazard switch is off, the hot wire leading to the flasher reads just under 12 amps. Again, the car is off and the key is in the ON position. That seems to be ok to me, correct me if im wrong. So i guess my problem lies somewhere from the hazard switch to the flasher or from flasher to the blinker connector... 

 

 

[Captain Obvious]

For diagnostic testing, you can completely eliminate the hazard switch from the system. I did this once or twice to drive around with no center console while still having functional turn signals. Goes like this... There are two large connectors near the passengers feet that connect to the console. On the wiring diagram, they are C-7 and C-8. The one in question is C-7 and it contains the supply and return wires that lead to the hazard switch. Unfortunately, C-7 and C-8 are both black, so I can't use color to distinguish between the two, but for ID, C-7 is a ten cavity shell and has all (or almost all?) locations populated, while the other connector C-8 only has maybe five of it's cavities populated. That should be enough info to identify C-7.

Disconnect C-7. You should be able to do that just by pulling the rug down. You don't need to take the console out. Just move the rug out of the way.

On the car side of C-7 (not the console side, but the car side) jumper the green/yellow to the green no stripe. Note that there are two green wires, and the one you want to jumper to is on the same side of the connector as the green/yellow. By disconnecting C-7 and jumpering those two locations together, your turn signals should be getting full power even with the hazard switch completely removed from the system. Should help narrow down the fault location. Here's a pic showing what to jumper:

I've had problems in the past with corrosion creating intermittent and poor connections on C-7 and C-8. I suspect it was instigated by moisture from a heater core leak sometime in the past before I owned the car. I cleaned up all the contacts in both those connectors and my problems went away.

[Premo34]

Thanks all the feedback so far. I'm going to work on it this weekend. Last night had time to disconnect the two connectors on the passenger side. They were almost green in color from corrosion. I cleaned those up the best I could using steel wool and sandpaper. Once i connected it all back up I had no power at the hazard switch! HAAA   These cars are touchy! So ill now be investigating why i have no power at the hazard switch too. It was still kind of light outside and hard to tell, but I'm pretty sure the dash lights don't work now either. Still have headlights/highbeams/seatbelt light/brake light. 

Like i said ill work on it this weekend and report back.

[Captain Obvious]

Exactly. If your C-7 and/or C-8 were green with corrosion, then that can certainly cause the problems you're having. I cleaned both of mine up really well, added some contact cleaner/lube, tightened up the contacts a tiny bit, and I've been happy since.

I've made mention about it before, but here's a basic Classic Z Car repair axiom... "You get a spare moment, clean some connectors."

[Premo34]

So I've been messing with the wires for a couple days...tracing and cleaning wires and connectors. Yesterday I did all that with no results. Today after work I try again jiggling some wires messing around. I'm not sure exactly what did it, but my blinkers work now. All lights are functional now even the dome light which didn't work before. So I've come to the conclusion that there is a short in a wire somewhere. Now, the dash lights and hazards come on only if the car is running and the red brake light will come on and off randomly when e-brake is applied.

 

Thanks everybody for your help! 

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[Mark Maras]

 Not a short, a bad connection. It can be on the supply side, +, usually corroded connectors could also be broken wires or missing or disconnected ground connections. If it was a short circuit to ground, a fuse would have blown. Start looking around the area that you were jiggling. You're close to the problem.

[Premo34]

Thanks for clarifying. I'm definitely no electrician. My guess is corroded connectors. The two connectors, c-7 and c-8 that Captain referred to are pretty green and nasty on the side where the wires go in. I did pretty good to clean the male prongs.

[SoCalJim]

My new-to-me 1975 280Z didn’t have working turn signals when I bought it a few days ago.  So, this morning I set out to get them operational.  When I measured voltage on the common pin of the turn signal switch (Green) with the switch in the neutral position, I saw normal battery voltage.  Then, when I moved the switch to either the left or right position, the common pin ‘s voltage dropped to near zero.  

I next unplugged the 3-pin connector for the turn signal (the connector towards the left-center part of the attached photo) and ran a jumper wire to the common pin on each side of that connector, thus isolating the circuit load (turn signals) and associated wiring.  When I then operated the switch, the common pin’s voltage remained at normal battery voltage, and normal battery voltage also showed up at the pin for the left or right turn signals, corresponding to the position of the turn signal switch.  

I unplugged connector C-7 and saw the the pin associated with the ground (Black) was completely green with corrosion.  I cleaned that up and tested my turn signals.  They worked!

While I was feeling good about my accomplishment, I check all the exterior lights to make sure they were working.  The right parking light wouldn’t come on.  When I removed the lens and unscrewed the bulb, it was also corroded.  A little fine grit sandpaper cleaned that up and now all of my exterior lights work.  On to the next project...

[gwri8]

That's good that you easily found your culprits.  I would suggest that since you've found corrosion in some of the connections there is a probability that there are more in other connections.  When you get the chance  I would suggest going through every electrical connection on the harnesses and check just for preventive measure.  I recently did this and found some potential problems.  I replaced quite a few with new connectors and cleaned up the rest with DeOxit. Glad I did.  

[SoCalJim]

That's great advice, Greg. I’ll look for some DeOxit and start cleaning connectors over the next few weeks.  Hopefully, I’ll soon have a fairly reliable electrical system.

[Captain Obvious]

Glad you found the problems. Sounds like good detective work.

And clearly why we need the Classic Z Car repair axiom... "You get a spare moment, clean some connectors."