49 minutes ago, Captain Obvious said:

Weird. It should not be doing that.

So the first thing that catches my eye is... When the hazard flasher is in it's OFF state, neither side should be lit. At all. And when the hazard flasher is in it's ON state, both sides should START their sequential slide across the bulb face. Yours get completely out of sequence and sometimes your left side even remains lit when the hazard flasher is in it's OFF state. That should never happen.

The sequential feature requires the running of a new power wire (pink) to the rear of the car, but that wire is not necessary if you are running the lights in standard mode (not sequential). My spidey sense is telling me to check the integrity of that wire.

Can you program your assemblies to function in standard non-sequential mode and see what happens?

Next, can you put just the left side in standard mode and see what happens? (Left side in standard non-sequential and right side in sequential mode 3 - in to out and back)

Also, what year are you working with? I'll look at the wiring diagrams.

I can check the 12v pink wire, maybe my crimp is failing after the right side, not sure how that would play into sequential mode working fine while running off the battery but not the alternator though. Seems like a power quality issue from the alternator but nothing else appears to be affected

I haven't tried setting the board to standard flash with the +12v pink wire, I've only unplugged it. Thats a good idea.

Its a 1976. Shouldn't matter but the power antenna and rear speakers have been disconnected from the harness

Other "things that run when the engine is running" - the fuel pump? Maybe it's noisy. It's in the vicinity.

You can run the fuel pump without the engine running by propping open the AFM vane with the key on or by removing the small wire to the starter solenoid and turning the key to Start.

If you have AC and have it turned on that's another possibility.

p.s. I almost wrote this earlier but it seemed like might be a distraction - if it is electrical noise a condenser/capacitor on the power or ground lines might clean it up. I had a weird situation with a tachometer on my 76 that would only work if there was a condenser (like those on the alternator) on the coil negative circuit. Non-classical usage and not something that I can explain. But it was a real thing.

Edited January 22Jan 22 by Zed Head

26 minutes ago, Zed Head said:

Other "things that run when the engine is running" - the fuel pump? Maybe it's noisy. It's in the vicinity.

You can run the fuel pump without the engine running by propping open the AFM vane with the key on or by removing the small wire to the starter solenoid and turning the key to Start.

If you have AC and have it turned on that's another possibility.

p.s. I almost wrote this earlier but it seemed like might be a distraction - if it is electrical noise a condenser/capacitor on the power or ground lines might clean it up. I had a weird situation with a tachometer on my 76 that would only work if there was a condenser (like those on the alternator) on the coil negative circuit. Non-classical usage and not something that I can explain. But it was a real thing.

Running the fuel pump is a good idea. I don't think its overly noisy but the fuel pump in my daily is much louder so I might have a bad baseline.

Talking about out of left field ideas, I could insert a voltage follower into the turn signal wire on the left side, if there is really something weird happening with impedance, that could help (maybe).

4 minutes ago, Electrin97 said:

I don't think its overly noisy but the fuel pump in my daily is much louder

I meant electrical noise.

For anyone browsing the threads - https://en.wikipedia.org/wiki/Noise_(electronics)

58 minutes ago, Zed Head said:

I meant electrical noise.

For anyone browsing the threads - https://en.wikipedia.org/wiki/Noise_(electronics)

Ah, that makes sense. I was thinking mechanical noise -> weak pump -> higher current draw -> weird electrical gremlins

1 hour ago, Electrin97 said:

Running the fuel pump is a good idea. I don't think its overly noisy but the fuel pump in my daily is much louder so I might have a bad baseline.

Talking about out of left field ideas, I could insert a voltage follower into the turn signal wire on the left side, if there is really something weird happening with impedance, that could help (maybe).

Put the left side into mode 1 (normal blinking) and kept the right side on mode 3.

Looks like a full cycle is supposed to be 1.25 sec long. When the engine was off, both side took 1.25sec to complete a cycle (40% duty cycle for left side and 80% for right side).

Once the car was running, right side still had a cycle of 1.25 with an 80% duty cycle but the right side was erratic. I timed 3 cycles and got; 2.5 sec cycle (50% duty cycle), 2.9 sec cycle (40% duty cycle), and 2.5 sec (50% duty cycle). Looks like the overall cycle is half the frequency but with an erratic duty cycle.

Still need to test with car off but fuel pump running.

I was re-reading the emails I had with the LED manufacturer and I think I might have a new lead.

"The rate at which the LED taillight panels flash a turn signal is determined by the flasher module and whether the LED taillights are in sequential mode or not.

When the taillights have +12 volts power on the LED panel's Pink wire or the Running/Driving lights are On, then the taillights will flash half the frequency that is output by the Flasher Module. The front lights will flash at the same frequency as the Flasher Module. This is because the microprocessor must wait longer than one flasher module cycle to determine whether the +12 volt signal on the Brake/Turn Signal wire is a brake signal or a turn signal. After that determination, the microprocessor will start another illumination cycle.

 

When the taillights do NOT have +12 volts power on the LED panel's Pink wire or the Running/Driving lights are Off, then the taillights will flash at the frequency that is output by the Flasher Module.

 

If the two sides of the LED taillights are flashing differently, then they are likely being presented with different electrical signals.

 

I hope this explains what you are observing. If you have any further questions or if there is anything else we can do to help, please let us know"

In addition to the rear LEDs, I also have halo style headlights and the way I wired the running lights on them to an ignition source, not to the the side markers so my running lights are always on. I installed the headlights after I had done the taillights so that checks out why the initial test on the board was behaving as expected but now they no longer are. I'm still confused about why it is only the left side and not both sides since I wired the running lights up front in series from the from the same power source so I'd expect both rear turn signals to be affected.

And your halo headlights have a turn signal function? Another question: did you re-wire the headlights? (I ask because Nissan doesn't use the "standard" wiring scheme for sealed beam headlights.)

What's going on with the front signal bulb and socket? It's part of the full turn signal circuit. I browsed back but don't see it mentioned. Might have missed it. Swap the bulbs or LEDs or whatever you have up there and see if it follows.

23 minutes ago, cgsheen1 said:

And your halo headlights have a turn signal function? Another question: did you re-wire the headlights? (I ask because Nissan doesn't use the "standard" wiring scheme for sealed beam headlights.)

Halos also act as turn signals. The wiring for the low/hi beam part of the headlights is a direct plug and play, you do need to tap into the turn signal and a running light/ign power source for the halo portion.

6 minutes ago, Zed Head said:

What's going on with the front signal bulb and socket? It's part of the full turn signal circuit. I browsed back but don't see it mentioned. Might have missed it. Swap the bulbs or LEDs or whatever you have up there and see if it follows.

Front are entirely new LED (with correct reflector so Im not blinding people) drop in units. I didn't have time to swap bulbs but I did unplug the running light/turn signal portion of the headlights and the cycle on the rear is a lot closer but left side is still slower (not erratic this time though).

Edited January 22Jan 22 by Electrin97

Stretttccchhhh - the indicator bulb in the tachometer. Can't find it in the wiring diagrams but I know it's connected somehow.

Found it. It's a branch off the main light circuit from the combo switch. Would still be the plain old filament bulb unless you changed those also.

You're posting but I'm saving anyway...

Edited January 22Jan 22 by Zed Head