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stock 78 280z wiring problems


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This is the long and short of my problem: I have no blinkers working, but all the lights themselves work on the hazards circuit. The switches are clean and work, as well as the blinker relay when I connected it to 12V at the battery. When I hit the switch, no blinkers, no relay click, nothing. All the fuses are good, as well as the contacts to them (I checked the fuses with a multimeter across the contacts themselves.) Any ideas? The horn works as well as high low beams, which are all on the same harness. With the switch removed, I can jump them manually, but still no relay click or lights....

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First off, Welcome to Hybrid Z.

 

Ok, being as the blinker circuit goes through the hazard switch, (if the hazard switch is unplugged or malfunctioning, the blinkers wont work at all), my knee jerk reaction is to say scrutinize and continuity test the hazard switch completely and its wire harness connections real close. I’m sure someone here has to have a schematic of the hazard switch internals. I’m not sure on the hazard switch itself, but I do know that the ‘78 Z wiring was totally revised so the Haynes manual ’77 wiring diagram really doesn’t help ’78 owners in most instances.

 

Also, I moved this thread over to the 280 model specific section.

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Below is a schematic of '78 turn signals. Notice that power distribution is separate from the Hazards (two separate fuses and flashers).

 

Turn signal power is routed through the hazard switch (so the hazards can interrupt turn signals). Then through the flasher. Then the combination switch, and out to the bulbs. I would start at the fuse, and follow the above path.

 

There are no relays in this system. The only thing you should hear is the flasher.

 

 

 

78TurnSignals.jpg

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I guess I misspoke when I said 'relay', I should have said flasher. That is a great diagram though, mine is huge and literally an enormous spiderweb of wires. Correct me if I'm wrong, but according to the top of the diagram I should be getting power to the flasher unit whenever the hazards are off, right?

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Correct me if I'm wrong, but according to the top of the diagram I should be getting power to the flasher unit whenever the hazards are off, right?

 

Yes... with key on, hazards off, the GY wire at the flasher should be 'hot'.

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Wow, i guess I posted that last reply too soon, I jumped the green to green yellow as is shown in the lower diagram, and the blinkers work great!! Thanks a lot guys, turns out the inside of the haz switch was all corroded, clean enough to turn on the haz lights, but not enough to let the blinkers work. While we're on the topic of electrical, I have two other questions. The first is simple, but what is floor temp? I've never seen that in other cars. The second is how many switches do I have going to the 'brake' light that's in the speedo pod? I figured the two brake level switches at the master cylinder, but are there more? Even with the fluid level switches removed and turned upside down (so the floats would be reading 'full' ) the light still stays on.

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I jumped the green to green yellow as is shown in the lower diagram, and the blinkers work great!!

 

Great!

 

The first is simple, but what is floor temp?

 

For catalytic equipped cars.

 

The second is how many switches do I have going to the 'brake' light that's in the speedo pod? I figured the two brake level switches at the master cylinder, but are there more? Even with the fluid level switches removed and turned upside down (so the floats would be reading 'full' ) the light still stays on.

 

Check the switch at the E-brake handle.

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Check the switch at the E-brake handle.

 

 

Also, there is a pressure differential switch that the brake lines both go down to when they come out of the master cylinder. The purpose of this switch (it looks like a proportioning valve or something, total of four brake lines in it and a wire) is to make sure that both front and rear brake circuits are working. if for some reason much higher pressure is detected in one circuit than the other, at an extreme point of pedal motion the valve kicks in, closes off the lower pressure side, and turns the brake light on.

 

This switch gets stuck, or the wire goes bad.

 

There is also a thread on this that was recently updated in the "Ignition & Electrical" forum that might be of assistance, the subject should be enough for you to find it.

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