LED Dash lighting?
brett at cloud9.net
Fri Dec 23 21:37:43 EST 2005
On Dec 23, 2005, at 12:20 PM, Ingo Rautenberg wrote:
> So, since I'm going to be replacing the dash pad and some
> instrument cluster lights, etc. tonight, I was wondering if anyone
> has done LED lights for the 200/V8 instrument cluster? I know
> people have done so with the window switches, dash switches, etc.
> Or do they not dim like traditional light bulbs? If they do dim,
> I'd like to know which ones to get (want to keep red lighting).
> And, yes, I can solder...
This has been mulled over for years on the mail list, and I'm not
sure anyone actually did it.
I have a tach courtesy Mike Sylvester (thanks Mike!) that I was
playing around with- the lighting scheme is actually pretty complex.
The tach for example is lit by no less than FOUR bulbs, and the gauge
face is a multi-layer setup that has patches of different levels of
The plastic light guide (which is also the body of the gauge itself)
has prisms(basically just 45 degree faces) cast into it around the
shaft for the needle; the needle is open in back and uses a prism
incorporated into the shape of the clear plastic to bounce light
coming straight out from the gauge face. The two bulbs on the
outside edges of the face supply light to the pointer; light is
bounced at the gauge edge (again, a 45 degree face which acts like a
mirror) into the center, then straight out via the cast prisms
You could most likely get away with LEDs on the outside bulb
positions because they collect light mostly dead-on, but the inside
bulbs are used for dial face illumination and light is transmitted
via cylinders which have an inside beveled edge (again, acting like a
prism- the bevel is probably level with the filament.) An LED would
work, but only if it was the kind that casts light full-circle to the
sides. They do make LEDs with integral reflectors for this kind of
dispersal pattern, if you poke through a catalog like Mouser or Digikey.
This is another solution to the problem:
Note the 45 degree prism face to distribute light to the sides. Too
big, however, for the dash...wrong bulb base style as well.
This place, however, has bulbs that might work:
Page two, skip down to the T1.5 twist-lock bulb. Pretty much the
As for color-matching, yes...there are a wide variety of "red" LEDs
at different wavelengths, but as long as the instrument cluster is
all the same and not very amber-ish, that's good enough for me.
Anyone already have their cluster out, so they can check to see how
even the illumination would be with these bulbs? Actually, I think
Lee Levitt was going to take his out to fix a mis-installed warning
light. Maybe he has yet to do it and wouldn't mind being guinea
pig? I'd do mine, except I absolutely HATE removing my cluster, so I
don't want to be the guinea pig. I do have a few bulbs out in the
cluster though...mostly the ancillary gauges.
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