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Re: [Re: Headlights]

To: Roadster <roadster@texoma.net>
Subject: Re: [Re: Headlights]
From: Michael Shimniok <michael.shimniok@usa.net>
Date: 6 Dec 2001 13:00:19 MST
Hm... wow, that's weird and yet... similar to my stop light experience last
night. :) Glad I'm not alone in the head scratching. :)

I've been sitting here thinking about this for hours. :)

The stop taillights were very dim with parking lights off and didn't work at
all with the parking lights on.  (68 where the top taillights are stop, bottom
are for turn signals)  Top parking lights weren't working, either.

I found both ground wires for the stop lites were disconnected.  So what must
have been happening is that the 12V was passing through the stop light switch
to the stop light filament, then with no ground path (since the housings are
plastic), it'd pass through the bulb casing, up through the parking filament
in the same bulb, then out through what should be the power wire for the
parking filament, then to the common power contact for ALL the parking lites,
through their filaments, and through their grounds.  That's a lot more
resistance than just a single filament. :)  And as soon as power was applied
to the parking circuit positive wire it would remove the ground path for the
stop lights.

Maybe your headlamp was grounding thru the hibeam circuit in a similar
fashion?  That is, passing through the low beam filament (as normal), then
grounding on the common high/low beam ground, back up through the high beam
filament in the same headlamp, across the high beam wire to the other side's
high beam, and also to the indicator lamp, and down through the filament to
the (working) ground?  That would mean the fuse is on the ground side of the
low beam filament which is either a mark of insanity or genius. :)  It'll be a
long time before I figure out the wiring diagram.  Looks more like a maze to
me. :)

Anyway, the latest set of electrical problems on the 68 are fixed and a new
set of halogen headlamps installed.  I'm no longer going to wonder what's next
because I'll likely find out. :)

I'm sure it's already been written about or most know how but if there is any
interest in replacing the oem relay with dual modern relays, I'd be willing to
write up something.

Michael

Roadster <roadster@texoma.net> wrote:
> Michael Shimniok wrote:
> 
> >  I'm confounded as to how the
> > wiring works.  Can anyone spend 20 words explaining it?
> 
> Mike, I've spent the last 20 years in industrial electrical,
instrumentation,
> and controls.  The wiring on this car beats the hell out of me!
> 
> Example: One night I noticed that one headlight was normal and the other
was
> very dim.  The old tungsten headlights used to do this so I replaced the
> sealed beam.  No change.  I then noticed that the high beam indicator was
on
> but it was on low beam lights.  Plus, the high/low switch had no effect on
the
> lights or the indicator.  I spent many hours chasing around the schematic
and
> the car.  I noticed that the left and right headlights have separate fuses
but
> paid little attention as the light was dimly lit.  Finally, out of pure
> frustration, I took a look at the fuses.  The one for the dim light was
> blown!  I replaced it and all has been well for the last 25 years.
> 
> I have since spent countless hours with a schematic trying to figure this
> out.  The wiring in the car has been gone over completely: no sign of the
PO
> mucking about.  I don't know if this is intentional or some kind of fluke
but
> there is nothing on the schematic to indicate why it should happen.
> 
> In fact, if anyone can explain this I would like to hear it.
> 
> 
> Best regards,
> 
> Fred Schroeder
> '70 2000
> SRL311-13359
> TDROC
> Home page http://home.texoma.net/~sitsinwest/
> Regular e-mail  Sitsinwest@texoma.net
> 
> 


---
Michael Shimniok  - KC0EKI -  "A computer without Microsoft
Michael.Shimniok@USA.NET       is like a dog without bricks
http://pw2.netcom.com/~shimniok/       tied to its head..."

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