Sold on LEDs

[Captain Obvious]

Yes, those dimmers are three wire devices with:

1) A 12V connection that controls the internals of the module
2) A pulse width modulated output connection that pulls the low side of the bulbs to ground, and
3) A ground connection for both the internal electronics and the bulb current.

I made some internal changes to the electronics on mine such that I could run it in two wire mode if I wanted to. Still works in 3-wire as described above, but as long as I keep at least one incandescent in the system somewhere, I can run mine in 2-wire mode as well.

[TomoHawk]

Did we ever discuss  the effectiveness of color on gauges? 

My Zed has green domes over the bulbs in the gauges.  All the aftermarket gauges I've seen (on hotrods) have white light (with with faces.)  I know blue gauges are bad because blue is hard to see in the dark.  GREEN is in the middle of the spectrum with blue on the one end, and red on the other.  That suggests green is 'OK' to light gauges.  Personally, I don't mind green, but I will just use the plain white LEDs for this summer, with the middle gauges being green, because I look at them much less often, and maybe  color the them all  green after  using white light for the summer.

I haven't found any discussion regarding gauge color (yet) but if you know of a good one, please share it.

[dmorales-bello]

12 hours ago, TomoHawk said:

Did we ever discuss  the effectiveness of color on gauges? 

My Zed has green domes over the bulbs in the gauges.  All the aftermarket gauges I've seen (on hotrods) have white light (with with faces.)  I know blue gauges are bad because blue is hard to see in the dark.  GREEN is in the middle of the spectrum with blue on the one end, and red on the other.  That suggests green is 'OK' to light gauges.  Personally, I don't mind green, but I will just use the plain white LEDs for this summer, with the middle gauges being green, because I look at them much less often, and maybe  color the them all  green after  using white light for the summer.

I haven't found any discussion regarding gauge color (yet) but if you know of a good one, please share it.

This comes from an aviation forum:

"The use of blue green lighting, however, has several benefits. Blue-green light falls naturally on the retinal wall and allows the eye to focus easily on maps, approach plates, and instruments; blue-green lighting results in less eye fatigue. In addition, the intensity necessary for blue-green lighting is less than that for red lighting and results in a decreased infrared signature as well as less glare. When blue-green lighting is used properly, the decrease in light intensity and the ease of focusing make it more effective for night vision."

And this comes from a forum on night vision:

"Conclusions:

• No matter what your color choice it must be fully adjustable for intensity.
• If you need the fastest dark adaptation recovery and can adjust to the limitations, or everyone in your group is using night vision equipment then blue-green.
• If you must see detail (reading a star chart, or instrument settings) and can lose peripheral vision ^{(see note 1)}, then a very long wavelength red at a very low level.  Red really only has an advantage at very low levels (were the night blind spot is very obvious).
• A general walking around light so that you don't trip over the tripod, knock over equipment or bump into people, then blue-green with enough red added to get rid of the night blind spot, or maybe just use white.  Blue-green at higher brightness also works very well and at a lower intensity than white.
• If you need to see color and detail then likely the best choice is the dimmest white light for the shortest amount of time.
• If you are in the military you must follow their rules; hopefully they will have a good course in unassisted night vision.
• If you are a pilot and say you only fly in the day, you should be aware of the problems of night vision and should consider a basic (ground) course in night flying.
• If you wonder why no one else has drawn these conclusions look at the dashboard of most cars.  The markings are large, the pointers are large and an orange-red (a compromise, for certain "color blind" persons) and at night it is edge lit with blue-green filtered fully intensity adjustable light."

It seems like blue/green lighting with adjustable intensity would be the best color for dash instrument illumination.

[TomoHawk]

Speaking of LEDs in the gauges...

I put the tachometer in, started the engine, and the needle moved, which is a good thing.

Then I turned on the lights, and the tachometer stayed dark.  The center gauges had lights.

I  tried an incandescent bulb, which lit up, but switching back to the LED made no improvement.  Then I took the gauge out and checked the wires and sockets.  The contacts were fine (clean) and had the correct colors (GW to the tip, and RL to the other.)

Then I got the tester (a 2V buzzer) and probed the connector.  I found that both the wires for the bulbs were hot.  May there's something to make it seem that way?  The LED doesn't like it.

I will dig into the wiring diagram, but in the meantime, may I get some help with this?  Getting the gauges i is the last thing to do to be ready for the summer.  I even got the PWM dimmer hooked up, and EP34 flashers for both the turn signals and the hazard lamps.

[Captain Obvious]

So the wires got hot with the LED installed, but were OK with an incandescent? Which LED were you using?

Even though it really shouldn't get hot, it sounds like a polarity issue? One thing to check... You said that the GW went to the tip, and RL to the base, but that's not the whole story. Since the polarity didn't matter in the original configuration with incandescents, the people who slid the contacts into the plastic connector shells didn't pay attention to which went where.

So just because the GW goes to the tip of the bulbs at the tach, it may have change polarity at the connector shell. You need to check the wire colors on both sides of the connector. (Or do your checking with a meter to a known ground source like a screw head.)

[TomoHawk]

The two wires weren't hot at all, but they had +12V on them, according to the buzzer. The incandescent bulb has no polarity, so it worked, probably finding its own way to complete the circuit. I tested the wires with an LED and some test leads, and I think the hot wire was fine, but the one going to the rheostat is getting some voltage, even with  the rheostat disconnected.

It's just confusing because I assumed all the gauge bulbs are in parallel, so why is the tachometer different?

I checked the wires to make sure the colors were the same on both sides of the connector, and they were- IIRC.

BTW-  I'm using the same paddlewheel LEDs in all the gauges, but I just got some 24-emiiter paddlewheel LEDs , so I put those in the two tachos.  There shouldn't be any difference in function; only the current and light output is different(slightly.)

Edited April 17, 2016 by TomoHawk

[TomoHawk]

One of the bulb wire has some heat shrink  on it, so I think it had a nick and was repaired.  The other bulb wire was not repaired.

Edited April 17, 2016 by TomoHawk

[Captain Obvious]

Ohhhhhhhh. When you said "hot", I thought you meant warm to the touch. "Hot" as in "voltage on both sides" is much easier. So the reason you're seeing some voltage on both sides of the bulbs is probably two things:

1) It's completely expected to have voltage drop across your rheostat, and in fact, that's the way it works. The rheostat divides the total voltage of the system to a smaller amount across the load and the remainder across the rheostat.

The PWM does the same thing, but it does it as a "time average" pulse instead of a constant DC level. And the dimmer the bulbs, the more voltage across the rheostat to ground than across the load (the bulbs). And in fact, with the rheostat pulled completely out of the circuit, you'll measure the same voltage (12V) on both sides of the bulbs.

2) You're using a "buzzer" tester and who knows at what voltage that thing decides to buzz. It could be 11.5V, or it could be 1.5V.

So, here's what I would do. First, trade out that buzzer tester for a voltmeter that actually gives you numbers, and measure both sides of the bulbs to a known ground. Second, I would take the LEDs that are giving you problems in the tach, and swap them for a known working pair from the speedo and vice-versa.

See if you can quickly narrow the problem to an issue with the tach, or an issue with the bulbs.

[TomoHawk]

I was thinking there wasn't enough of a potential difference to drive the LEDs, because the LEDs worked fine when bench testing.  Even with the rheostat disconnected, and the connector shunted, the tachometer LEDs were off, with the other gauges at full brightness.  Maybe there's a loose pin in the connector, who knows...

BTW, I have all LEDs now in the gauges.

Edited April 17, 2016 by TomoHawk

[TomoHawk]

Can you say mixed up pins?  Mark up another zero for early Nissan "quality control."

After a couple tries we got the lights working and the thing still shows the engine speeds too. The other tachy  only has bulbs for electrical stuff and it has the connections for the bulbs correct.  I will only be using the LEDs for the gauge illumination, and I will put in some new incandescents for the brake & high beam indicator, as they only go in occasionally as opposed to the illumination.

The PWM dimmer is next... 

[TomoHawk]

I'd like to try some LEDs in the map light.

I think you can get a COB panel about 16 x 30mm, which ought to fit just behind the clear lens  and create a good flood of light, compared to the original design.  Or you could try a  powerful 194 bulb with LEDs like this one, or this one.

Edited April 18, 2016 by TomoHawk

[Captain Obvious]

Mixed up pins? That's what I found as well. The polarity changed at the connector.

Map light? I'm using one of these in warm white and I really like it. Brighter than stock, great dispersion, and short enough to fit into the original housing without modification: