Re: [T3] Brake warning light wiring on 68 Squareback

[Matthew Willis <mattwillis@mac.com>]

<x-flowed>On Wednesday, July 30, 2003, at 04:42  PM, Jim Adney wrote:

> On 30 Jul 2003 at 13:37, Matthew Willis wrote:
>
> > The brake warning light in my 68 Squareback has been coming on 
> > whenever I
> > press the brake, although the brakes seem to feel and stop well. I 
> > figured I
> > would check the wiring since it could very be an electrical problem. I
> > received my Bentley today, but its 8/66-7/69 wiring diagram doesn't 
> > include
> > the warning light!
>
> It's in the brake chapter.

Yeah, but I thought the diagram was for post-68 cars without the 
separate warning light contacts...which brings us to your next point...

> BUT you probably don't have the original MC anymore, so your's has 
> probably
> been changed. 68-9 had 3 switches on the MC, but starting in 70 they 
> made the
> system much simpler and just used 2 switches that were each more 
> complicated.
> It is likely that one of your switches is bad or is wired up wrong.
>
> Tell us what you see on the switches on the MC.

Without getting under the car, becoming a contortionist, or tearing a 
boot, I could remove one of the two wiring boots covering the brake 
light switches. The switch had two terminals, with a red and blue wire 
attached. However, I found there were three looms in that area, and one 
was ziptied up and out of the way, not connected to anything, with 
masking tape over the spade connectors. Three wires inside: blue, grey 
or white with red, and green/tan/brown?

Pics are at:  http://homepage.mac.com/mattwillis/PhotoAlbum5.html

Here's my take:
The MC indeed was replaced at some point, and the replacement was the 
newer model, without the separate warning device cylinder.
Joe Mechanic simply installed the two existing brake-light-only 
switches, tossed the warning light switch, and tucked the wire up out 
of the way, rendering the warning light pretty, but useful only as an 
internal brake light.

Does this sound plausible or even electrically possible? If the 
separate warning light wiring was simply disconnected, how would the 
light inside sense my brake pressing? Are these even close to the wire 
colors for that switch on a 68? I can't find them on any wiring diagram 
I've looked at.

The plot grows thicker...

-lilmatt

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