1972 dash illumination

[Scot Minesinger]

I do not have any problem at night in my 1970 Cadillacs.  It is unlikely that this lack of illumination suffered was the intended factory design.  There has got to be an issue.  I usually turn mine down a little because it does help you see the road better.  Something is wrong, probably the switch.

[bcroe]

There are a lot of problems with old dash/speedo lights.  One was
that rarely serviced, the bulbs got coated inside and dim, and some
just burned out.  This was quite likely when servicing them is quite
difficult. 

Another is that the bulb mount gets oxidized and makes poor contact,
or the heat actually distorts the board.  I have fixed some of these
with small wires soldered around the contact, just long enough so the
mount can be removed and the bulb changed. 

A 79 E car just seemed to always be too dim at night.  I finally
discovered that the speed face was a bit too close to the outer
frame, and the surrounding gap was too narrow to let much
light through. 

I see LEDs a a final, permanent fix to the problem. Very long life,
very little heat.  Substituting them for bulbs leaves the problem
of possibly too bright, original dimmer ineffective.  First, I may
glue the strip version inside, forget the bulb mount.  The brightness
I set with current limiting resistors, I use the same setting all the
time.  They may just be wired to the head or tail light circuit, the
original dimmer may still serve incandescents like the radio.  Or
just to the 12V present to power gauges.  On in the day time,
does not matter. 
good luck, Bruce Roe

[67_Eldo]

LEDs are current-driven devices while incandescent lights are more voltage dependent. That's why the original rheostats in old cars have no effect on LED replacement bulbs.

To control LED brightness, you typically want PWM (pulse-width-modulation) devices feeding LEDs. If your "pulses" of current are shorter, the LEDs will get dimmer.

Since SuperBrightLEDs has been mentioned, here's an interesting little PWM control that would work in an old car:

https://www.superbrightleds.com/moreinfo/single-color-dimmer-switches/itouch-12-24-volt-dc-touch-led-dimmer-6-amps/1867/4380/

[The Tassie Devil(le)]

Did they say why the part is being discontinued? Obviously there is a larger market these days for products like this. 

I did ask that question, but thus far, no reply that would satisfy my own curiosity.

Bruce.

[bcroe]

Pulse width modulation can be used, I have used it on Nixie tubes.  But
some sort of current limiting will still be need to be in place.  It will
generate radio interference, and looking away from it may appear to be
a string of dots.  Bruce Roe

[Julien Abrahams]

I don't have a problem driving at night either. In comparison to some other (English) classic cars that I own the dash on the Caddy lights up like a Christmas tree with a bulb in practically everything, from windshield wiper switch to radio. Also there are 5 bulbs just for the dash itself, at least in my '67. When i first got my car three bulbs where burned out and the headlight switch worked Intermittently. After replacing the burned out bulbs and the headlight switch, everything lights up nicely at night. Could you maybe snap picture of the current situation so people on here can compare? Good luck,

Julien.

[Roger Zimmermann]

No yet. My dash is looking like that for the moment...Even worse as I removed the dash bezel for various reasons.

[Julien Abrahams]

I can see why that would be a challenge 😂😂

[Roger Zimmermann]

It went worse! As I could not remove the light switch with the known method, I removed the dash's bezel! While I was doing that, I found a bracket wich was attached loose with one screw; I have no idea about its purpose. If somebody would know it, I'm grateful!
In fact, the light switch is looking like new. After I reassemble most element from the dash, I did a test with the standard bulbs. As it was not completely dark in my shop, that test is not quite definitive; it could be that before I remove the cluster in miles not all bulbs were functioning. 
In between, I got the LED bulbs. I will soon replace some with those Made in China bulbs and will report.

[The Tassie Devil(le)]

A picture of the "loose" bracket would be nice.

Bruce.

[Roger Zimmermann]

Bruce, on this picture, a red arrow is pointing at that support. If you would like to have a picture from the support alone, it can be done as the lower panel is not yet installed. I'm glad I'm not too thick to lay on the floor; by removing the front seat, the task would be easier...

[The Tassie Devil(le)]

G'day Roger,

I had a look under the dash on my '72 Eldo, and there is some sort of bracket which could be the same as yours.   Have a look in my pictures, and if so, I will dig deeper, and get a better photo, from a less cramped position.

Plus, I did see stuff that I didn't notice before.

But, it took me another 10 minutes to extricate myself as I slipped off the seat and laid on the floor.

The last time I saw those little bug nests was in the confines of my boat which I imported at the same time as the car.

Plus, the pedal bracket is well covered with surface rust.

Bruce.

[Roger Zimmermann]

Well, Bruce, I'm seeing that bracket on your first picture, but not on the second (It's maybe too early in the morning?). At the other end of the bracket, there is a hole, but no indication that a screw was torqued. As there was some previous repair done under the dash, it's hard to say what "they" forgot or discarded.
I'm sorry that you had such a long time to go out of the car; obviously you are not as thin as me as I need about 30 seconds for getting out!
Maybe today or tomorrow I'm going to my garage. I will try to make a better/clearer picture and install those LED bulbs (pardon: globes).
I forgot  first to thank you for the pictures and, second, to say that all unpainted brackets under the dash have almost the same red color than yours! But I have no bug nests!

[The Tassie Devil(le)]

I will have a deeper and better look tomorrow, when I have someone to assist in my extraction by pulling me by my feet, as the Eldorado has a flat floor.

With all that wiring behind the dash, trying to see what is there is difficult with the dash in place.

At least yours with the hump would stop one falling all the way down.

Bruce.

[Roger Zimmermann]

I'm not lying the way you do: the most part of my body is out towards the door and only the shoulder/head are on the floor. Not excessively comfortable, but I'm surviving! Because of the hump, its more difficult to have the legs towards the passenger side and the head down, but it can be done too. To repair/maintain such large cars, you have to have a flexible body!
If you have some pounds too much, I understand the difficulty you have to extract yourself from the floor!

[The Tassie Devil(le)]

I am rather svelte at 117 Kg, and 197 Cm tall.

Bruce.

[Roger Zimmermann]

I am rather svelte at 117 Kg, and 197 Cm tall.

Yes compared to a ….(I don't want to offend you, I let choose what you want)! For such kind of work, I'm glad with my 171cm tall and 58 kg!

[chrisntam]

I am rather svelte at 117 Kg, and 197 Cm tall.

Bruce.

For us americans, 117 Kg is 257.941 pounds; 197 cm is 6.46325 feet.
Roger is 5.61024 feet & 127.868 pounds.  Roger, you need a sandwich or two!  And dessert!

Being tall is great when things are up high, but when things are on the ground, it's getting harder to get them!  I think being smaller working on cars is an advantage.

I'm 6'5" (195 cm), 225 pounds (102 kg).

As a side note, my older brother is 6'6" (198 cm) and he likes early vettes. His kids laugh at him because when he drives them, his head is above the windshield.  I guess that's why I like big cars, because I'm big and I fit in them.

[Roger Zimmermann]

This afternoon, I replaced that standard bulbs with the LED ones. What a difference! As it's raining, the natural light in the garage is poor. With full illumination, the dash has a light similar to the one from the clock with 2 bulbs @ 3 cp each. The best is that the rheostat is working! I'm glad I did that change.
To Bruce: I'm adding some pictures from that support. As the lower panel is not yet installed, it was not too difficult to have decent pictures. If we don't find the usage from that support, I will discard it.

[The Tassie Devil(le)]

Roger,

STOP THE PRESSES.   I have found it.

If you enlarge the pictures, you will see it, pointing horizontally.

Now i just have to figure out what is attached to it.

Oh, I love photos.

Bruce.

PS.   In my car the bend is towards the centre of the car, whereas your piece is bent to the outside of the car.   I would hazard a guess that my car is original, and with yours being loose, it probably has been taken off, and not put back correctly.