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Led dash lighting

9K views 10 replies 9 participants last post by  dmericas 
#1 ·
With the dash removed from my Alfetta to install A/C I decided to replace all the gauge and indicator lamps with LEDs. I'm sure most of us are unhappy with the dim lighting in Alfa dashboards, so my desire was to improve the lighting level while using lamps with a very long life. LEDs were obviously the way to go, if I could find them, and it wasn't easy. The Alfetta uses a very tiny lamp (15 of them) that is all glass (no metal base), and is about 3/4" long x 1/5" in diameter and puts out a mere 1.2 watts. Matches are brighter! This lamp is known as a "midget T1-3/4 wedge base". It appears they are available from Centerline for $1.95 each. I eventually located the LED equivalent which is variously known as a "WF200", or a "74" from superbrightleds.com for $2.49 each. Now, with LEDs you must use the same color LED as the lens in your dash - - in other words you can't, practically speaking, use a white LED behind a red lens. So, I bought 5 Red (#74-RHP3), 1 Amber (74-AHP3), 1 Blue (74-BHP3), 2 Green (74-GHP3), and 6 Cool White (74-CWHP3) as well as 6 Warm White (74-WWHP3). The reason I duplicated was I didn't know whether I'd like the Warm White (which emulates the old incandescent) or the Cool White for instrument lighting. The result is I prefer the Warm White for authenticity. There is no difference in overall brightness. Alternately for a modern look I tried the blue and the green in the instruments. The green does an effective job, but the blue is a little dim. Overall the brightness of the LEDs is maybe double what the old incandescents were (at 1/8 the current draw!), and I anticipate never having to replace them again. NOTE when you install one and it doesn't light, reverse it and it will, because LEDs are polarized. Superbrightleds have many more sizes and styles of auto lamps, so they are a very good source for modern LEDs.
 
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#2 · (Edited)
White LEDs are bad for night vision, as the shorter wavelengths of the blue light part of the emitted spectrum causes the eye to partially shut down, reducing night vision capability.

The same problem exists for LED streetlights if the lights are the white/blueish color.
To quote the medical report as reported on CNN: "The first (problem) is discomfort and glare. Because LED light is so concentrated and has high blue content, it can cause severe glare, resulting in pupillary constriction in the eyes. Blue light scatters more in the human eye than the longer wavelengths of yellow and red, and sufficient levels can damage the retina. This can cause problems seeing clearly for safe driving or walking at night".

side note: Some cities are finding that people do not like the glaring of the modern LED streetlights. Davis, CA had to take them back out because of citizen dislike. Seattle has started to install some, and I sure don't like them myself, they being pretty glarey/dazzling in some cases, esp in the rain.

I personally like plain old incandescent bulbs, with their warm spectrum, for the car dash. Most people these days tend to turn them up too much anyway, reducing their night vision capability. I see people driving around at night with them on maybe full bright. Yow.

I like them just bright enough to just see the instruments, no more. The darker, more rural the road, the dimmer I can have them. Never found the dash lights in any of my Alfas too dim for comfort or safety, except the tiny pinpoint lights on the center console of the LS. Those could be just a bit brighter, or better yet, softly glowing panels as with my original 64 Sprint GT dash warning/indicator lights. Those I liked, big enough to see, but not bright at all. Not distracting or glarey.

Just an observation.
 
#3 ·
I've started installing LEDs in my Spider, and they make it so much more comfortable when driving at night. Less second guessing what I'm looking at, and then no more thinking "how can make this brighter". Superbrightleds.com has a great selection; just have to do your research to make sure you are getting the best replacement.
 
#4 ·
Let me make a correction to my original post about LED lamps for use in dash and instrument lighting. I said, "with LEDs you must use the same color as the lens in your dash". That is true with the colors red, green, blue, etc. but not with white LEDs. The non-whites each emit only a true primary color, in other words a red LED emits only red light. The white LEDs, however, are most often made by mixing very tiny individual red and blue and green LEDs which results in a white light output. So, if you put a white LED behind a red lens, the lens will filter out the green and the blue but not the red. That indicator will glow red. However it will be less bright than if you used a red LED behind that red lens, because roughly 1/3 of the lumen output isn't shining through the lens, it is being filtered out. On the other hand if you put a green LED behind that red lens it will absolutely show a green output (try it). Ditto the other color combinations. So, since these lamps are all the same price regardless of color, if your goal is maximum light output, install the same color LED as is the lens.

Another thing I forgot to mention is these LED lamps are basically not dimable. If you turn the rheostat down they might dim a little, but will then suddenly go out. That is the nature of LEDs. So, be prepared to either have your rheostat turned full up, or simply bypass it entirely with a jumper wire. As I stated in the beginning, the primary goal was to make the dash lights as bright as possible. With the exception of DEL, I don't think you will find them to be too bright.
 
#5 ·
I got the 6 LED festoon bulb in warm white for the two B-pillar cabin lights (or glovebox, rearview mirror light, etc.) and it is like daylight. I can actually see things when I want to and even read a map. It is a bit wide for some enclosures.
 
#6 ·
74GTV LED Conversion

I just completed the write-up on the LED Conversion on my 1974 GTV and hope the file size is small enough to enable posing for others to use. I am thankful to all other posts who got me started on this task. I spent a lot of money on "bright light" that were not so bright. But I am very happy with the results, especially the dash lighting. LED bulb spec and sources are listed in the attached file.

Good luck with your project.
 

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#7 ·
Great write up Hannau!! This is a project for the winter season, when the temps here get cooler, for each of the Alfas. Thanks so much for sharing with everyone. Very nice.
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#8 ·
If I was to take a photo of my Berlina tach or speedo at night I'd have to use an F1.1 lens wide open with a shutter speed of two days, er nights:) with an effective film speed of ISO 20000. They are that dim. This is great information, thanks!
 
#9 ·
Just replacing the original tungsten filament bulbs helps a lot as the smaller ones get a black/silver film inside over time, but no doubt the LED's in warm tones are better with lower heat with less consumption.
 
#10 · (Edited)
***IMPORTANT NOTE*** - socket shorts out!

I ordered 74-R LED dash light replacements (and they look GREAT, in my opinion!) from superbrightleds.com ...

ONE initial problem, though: My 1976 Alfa Spider used sockets that provide (+)12 VDC to one of the FLAT sides of the wedge base, and (-) to the other. This worked fine with the original lamps, because the contact wires were only on one side or the other, not both!

The replacement LED bulb runs the contact wire around to BOTH sides of the wedge base - which instantly shorts out the socket!!

SOLUTION: re-bend the contact wires to fully lay on each flat side of the wedge base. Not difficult, but necessary!!

 
#11 ·
I am converting the dash lights on my 1974 GTV to LED. I have a spare instrument panel that I've been using for reference. I was surprised to find that the small warning and signal bulbs are different in the two panels, as shown in the picture.
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The only other difference between the two instrument panels is that the odo reset cable on one comes out of the bottom of the instrument pod (smaller bulb), while on the other it comes out of the bottom of the dash (larger bulb). The bulbs are not interchangeable. The main instrument bulbs are identical (194?).

I'm wondering if the instrument panels are from different years?
 
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