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Turn Signals - Stumped


gotham22

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I have a 1978 280z that I am so close to getting back on the road after 4 years.  I can't get the turn signals to work and I am at a standstill.  After searching forums the obvious thing was to check the hazard switch (hazards work).  I jumped the green/yellow to the green at C7 to rule out the hazard switch.  With the wires jumped I see 12v at the turn signal.  Removing the jumper and keeping the hazard switch in-line I see 12v as well. 

As you can see in the picture, the connector to the turn signal has the following wires

G   WR  WB

GB  RY  RW

With the turn signal in the middle position I have 12v at the G wire and the GB wire.  When I move the turn signal to the up or down position the G wire drops to 0v and GB stays at 12v. When I return it to the middle position the G wire has 12v again.  

I also looked at the flasher unit under the drivers dash.  I have 12v on the green wire going in to it.  0v on the white wire.

At this point I am not sure what to do next.  Any ideas?

 

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To provide additional detail to the above... It sounds like your flasher unit is not making a good solid connection across it.

It's a low enough resistance to provide 12V at the turn signal switch when the switch is in the center position (driving nothing). But as soon as you move the turn signal lever up or down, the low resistance of the signal bulbs drags the voltage on the white wire out of the flasher down to zero.

I'm thinking your flasher is fubar. Or the connections on the base are corroded. Something like that.

I assume you already checked the connector condition right there at the turn signal switch? Everything all nice and clean and shiny?

 

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First, use the colors on the dash harness side of the connector, not the switch side of the connector. The switch colors do not necessarily match the wiring diagram.

The white wire is the 12 VDC source coming into the switch. There are two green/black wires. One is for the horn. It should have 12VDC to ground until to press the horn button. The other GB wire is for right side turn signals.

  1. Turn the key to the ON position.
  2. Verify you have 12VDC to ground at the W wire in the steering column. If you don't, you might have a bad flasher relay.
  3. If you have voltage at the white wire, then turn the switch up for the right turn signal. If the W wire is at 0VDC to ground, measure voltage to ground at the GY wire on the flasher relay.
  4. If there is voltage at the GY wire, you might have a bad flasher relay.

 

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Thanks for the info guys. 

- I do not have any corrosion that I can see on the connections. 

-Steve J - The white wire on the dash harness side connects to the green wire (where I took the reading) on the switch side.  Those two are the same right? So my voltage test was accurate?

dash side = W GB GR

switch side = G WR WB

Not sure if this is a dumb question. Is the hazard relay the same because those work? Could I pull that temporarily and use it for the turn signals? Or is there a way to test the flasher on the bench? 

 

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8 hours ago, gotham22 said:

Thanks for the info guys. 

- I do not have any corrosion that I can see on the connections. 

-Steve J - The white wire on the dash harness side connects to the green wire (where I took the reading) on the switch side.  Those two are the same right? So my voltage test was accurate?

Considering your first post was conflating the turn signal GB with the horn GB, I think you may want to go through the test I laid out.

8 hours ago, gotham22 said:

Not sure if this is a dumb question. Is the hazard relay the same because those work? Could I pull that temporarily and use it for the turn signals? Or is there a way to test the flasher on the bench? 

The flasher relay for the hazard lights is the same as the flasher relay for the turn signal. Yes, you could swap it over to test. However, both @Captain Obvious and I still wonder if the problem could be further upstream. That's why I prefer voltage readings over component swapping. However, swapping the hazard flasher relay would be much easier than bench testing the flasher relay. In order to have old style relays operate, they need sufficient current flowing through the relay to get the bi-metal strip to bend.

If you have a bad flasher relay, here is a two wire relay that still has a clicking sound similar to the old bi-metal flasher relay: https://www.amazon.com/dp/B07GWL1YS3

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Any chance it's the bulb(s) or their sockets?  When you say "don't work" do you mean no light at all, or no flashing?

I'd put a meter on the pins in the bulb socket.  Sometimes they look okay but don't actually contact the bulb terminals.  Plus you can test power supply and ground.  A look at the wiring diagram will show which pins do which.

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I think I got it.  Originally I stated I bypassed the hazard switch by jumping GY - G in  C7.  Turn signals did not work.  Then I connected c7 back and put in the new relay and it still didn't work.  Since I am positive this relay is good I tried jumping the wires in C7 again. Now it works!!  Seems like I have a bad hazard switch and a bad flasher relay.

 

You guys are awesome!  Thanks for the advice.  This was my last fix.  After 3.5 years I can get it back on the road!!

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Spoke to soon.

Hazards work, turn signals do not when wires are not jumped at c7.  I pulled the hazard switch apart to see what is wrong. Connectors look fine, no corrosion.  I ran continuity tests on the switch side wires to the board and all checked out. On the board  I can jump the hazards and get them to work but I can not jump the turn signals.  

With the ignition in the on position the dash side connector green wires both have power.   Where can I look next?

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I haven't followed the whole thread but the wiring diagram shows a different power supply and a different output through the Hazard switch, for turn signal versus four way flashers.  You're either not getting power or you're not getting output from the Hazard switch. I would confirm power in on G, then power out on GY, right at the Hazard switch, firstly.

 

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ok, I got it this time.  Finally! I started my troubleshooting over from scratch.

 1)Jumped G and GY at C7 again for a sanity check to make sure the turn signals worked. They did.

2) Took apart the hazard switch and cleaned up all the connections. Tested it with a multimeter and found no issues.

3) Connected G and GY from c7 directly to my switch. This worked

Problem was somewhere with the wires that connects C7 to my switch.  Ohms test was fine on all the wires.  Although I did not see any corrosion, I once again cleaned the male and female connections.  Then I sprayed it with deoxit.  Reconnected everything and now I have both hazards and turn signals working!

Damn this was not an easy one with two separate issues.  Thanks all for the help. Couldn't have done it without your help

 

 

c7-switch.png

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