4kq Instrument lighting - LED Question

[Craig Lebakken]

griz at myrealbox.com wrote:

"My original question was regarding the insides of the
socket. Seems that the
light has to shine
into/onto a small area of clear or red/amber plastic that
then shines onto
gauges. I want to
know if anyone has taken the cluster apart or broken one and
can tell me what to
expect.
So far it's been a pita getting light where it needs to be
since these LED's are

spotlight/pinpoint LED's, not diffusing light all around.
I.E. Hard to aim.
Dennis"

The lighting for these cars is kind of funky. Basically the
incandescent bulb focuses light into a diffuser of sorts,
which then spreads the light across the gages. I think the
part you might be missing is the focusing part. If you look
at these bulbs, they are abnormally thick at the end, almost
like having a lens built in. I think this "shoots" a
majority percentage of the light into the diffuser. If you
can find LED's with the same ability to focus light I think
you will be on to something. Another PITA that I found - the
excessive heat generated by the bulb AND light switch
results in local deformation of the plastic socket around
the bulb holder, and can result in loss of electrical
contact (i.e. loss of light). Tweaking the contact of the
bulb holder so that it extends further is a dicey solution,
as the plastic is not deformed at the entrance of the
contact at the socket, and when twisted in, can rip the
copper printed circuit that provides the power. It can be
done, with care, and now I have light on the left side of my
dash for the first time in three years. The fix for the
odometer didn't take however. Oh well, at least I can see.

HTH

Craig Lebakken
1986 4KQ