1973 Wiring problems - hazards and lights

[Sparky73]

Thanks Ed, yes quite a project car going here. Here are some more details.
Horn and steering column grounds are sorted out and working.
Wire harness was custom built from Restoration Design and the main harness and front trunk harness were built for a 73. The engine harness was updated to a 76 and for ITB's.
RD has been working with me to figure out the problem. Still no luck.

Here is where I stand. I have two issues
1. blinkers not working correctly
2. Hazard lights turn on when I pull the parking brake up

I believe it has something to do with the Hazard Relay

#1
With everything wired up, Blinkers are not working correctly
When I put on the left blinker, front and back blink as they should, but the right blinker also comes on dim
Same for the other side

If I remove the Blue/white (Emergency Flasher relay wire) to the back of the Speed gauge for the blinker illumination,
Blinkers works correctly, expect I have not dash blinkers since the blue/white supplies power. Each side blinks as it’s supposed to


#2
E-brake
When I pull the E-brake up, the red lights on the dash comes on and the blinkers blink
If I pull the blk/Green/white wire from the brake light switch and give it 12v power, the red light on the dash comes on as it should. Blinkers do not blink.


So, my two problems
Blk/whte/Green wire from Relay
And
Blue/White from Relay

Are both causing problems.

This is what I am down to.
1. I have not found the right relay that works with this set up

Or

2. Something is wired wrong to the Hazard plug. I checked the plug and got the following readings

[Sparky73]

I have all my grounds connected to those three points that you pointed out as well.

I do have a number of wires capped off, wiper motor, heater blower, license plate harness. All not needed to get the car started. I don't think those would be causing the issues I am having.

Not sure how to test the grounds.

[PeteKz]

Jared, IDR if I said this on another of your threads: Replace all the fuses with NEW. It probably won't fix this problem (although it might), but it will prevent other mysterious electrical problems. The open bullet fuses get old and tired, due to heat cycles and corrosion on the little metal strips. They develop tiny cracks that you may not see and that cause open or intermittent contact.

Do that every 10 years "whether they need it or not," and you will save yourself headaches. Fuses are cheap. Or you can do what others here have done and swap to the new fuse style fuse panels. Those are $400 or so, and take a day or more to install.

[E Sully]

Pete, good advice but in this case he has new wire harnesses and fuse panels.
Jared, there are quite a few fuses that could probably be removed from you panel as they are not used, but should not be causing your issues.
I will try to get into your wiring a bit more soon.
To test your grounds, use an ohm meter connected to the brown wires and the other lead to the chassis. You should see very low ohms. High resistance means there is an issue.

[Sparky73]

thanks guys. I have a new fuse panel, so that is not the issue.
I have removed a few of the fuses as well. Here how my fuse panel is set up. You will see a few fuses have been removed.

I am down to two issues
Blinkers
E brake

Blinkers work when I remove the blue/white wires to the back of the speedo gauge (this gives power to blinkers lights) This means no turn signal lights on dash

E-brake, when pulled red light on dash comes on but hazards blink. If I remove the Blk/Green/white from the back of the park brake indicator bulb, it stops working (this is how it gets power). If I give the indicator light 12v power with the E brake up the dash lights up as it should.

I have tried 3 different relays.

Still not sure what the issue is.

[E Sully]

I'm going through the wiring a bit here and there. The fuse panel looks good except for lighting is reversed left and right.

[Sparky73]

Thanks for looking at the fuse panel. What do you mean lighting is reversed, left and right ?

Still can't figure out this blinker issue. If I remove blue/white from the back of the dash gauge it all works right. Tried multiple relays, that does not seem to be the problem.

Thinking it's the harness???

[E Sully]

The fuse position of the left lights is 1&3, right 2&4 originally, yours shows right 1&3, left 2&4. It's nothing that would make a difference.
I am wondering about the aftermarket tail light housings. There is something about the wiring there that seemed off in that thread. I have to revisit it.

[Sparky73]

E Sully and all others that tried to help me here. I finally figured out the problem, or Peter from Restoration Design figured it out.

I replaced my blinker bulbs with LED's - DON'T do that.

The LED caused all the blinker problems. When I removed the front blinkers bulbs and put in old school bulbs, the system all worked.

Problem solved.

Thank you Peter, Restoration Design wiring guru. You are the man.

[spoke]

Originally Posted by Sparky73

E Sully and all others that tried to help me here. I finally figured out the problem, or Peter from Restoration Design figured it out.

I replaced my blinker bulbs with LED's - DON'T do that.

The LED caused all the blinker problems. When I removed the front blinkers bulbs and put in old school bulbs, the system all worked.

Problem solved.

Thank you Peter, Restoration Design wiring guru. You are the man.

Which blinker bulbs are you referring to? The exterior bulbs or the tachometer turnsignal indicators?

I think you still have issues. Installing LED turnsignals and running lights should not cause any issues except with the tach indicators. EP26 LED-compatible flasher relay corrects those. Folks change all their exterior turnsignal bulbs to LEDs with few issues beyond the flasher.

Before you found a solution with bulbs, it seemed your front turnsignals and/or headlights were not correctly wired. You said the rear turnsignals were bright but fronts dim. Regardless of LEDs or bulbs, front/rear should be bright. I think there's a ground in the front that needs attention. LEDs may exasperate an issue whereas incandescent bulbs may mask an issue.

[Sparky73]

Exterior blinker bulbs in the front, lower bulbs. I do have LED in the dash, but those don't seem to interfere. I also left the rear blinkers exterior LED and it works.

It could be a ground issue, but removing the LED blinker lights fixes the problem for now.

[spoke]

Do the LEDs in the dash work correctly? If you have LEDs in the rear of the car both L and R indicators in the dash may be both on together or off completely when the left or right turnsignal is on.

Generally if you have an OEM flasher relay with LEDs externally the OEM relay will not drive the L and R tach indicators correctly. LED-compatible flasher relay EP26 is a good replacement if the C2 pin is grounded internally.

[Sparky73]

Yes, Dash LED's work fine. No issues. I have a Wehrle
54 201 102 A E49 relay

Porsche OEM did not work at all.

At some point I will check the grounds and see if that was the problem, but I don't believe so.