Brake Lights

[Jeffrey.Deaver@domain.elided]

Hi All.

 With a new kid due anyday now, my '58 A-102 is quickly becoming my daily
driver as the Toyota wagon will be left home for the wife.  And wouldn't you
know it... the brake lights stopped working recently.   I have a service
manual coming, with the wiring diagrams, but need to get this fixed quick, as
you can imagine....

So, I started to study the problem last night... seems the switch for the
brake lights is attached to the master cyclinder?  I'm used to seeing a
switch that works with the pedal, but this was the only electrical - switch
looking thing I could find attached to the brake mechinisms.  Anyone know how
it works?  Does the fluid actually push a switch or something in there?  I
was reluctant to take it off fearing I'd end up having to bleed the entire
system.  It is a small, sort of round thing, positioned between the fluid
resovior and the line to the brakes with two wires running into it - one of
which subsequently does run back to the lights.

In anycase, I don't think its the switch, directly anyway.  I would assume
that one of the wires running to the switch (assuming that was the switch)
should be hot, but neither were (and yes, I had the ignition on).   Of
course, the wires run into another mess of wires all taped up, so its
impossible to trace them back without removing all the wrap around the
wires.... but I figured one probably went back to the regulator.. so checked
those.. all were hot, 12V, except one... but it was white.. and the wires to
the switch are green.. which I realize does not mean anything since it could
be spliced any number of places.

So the question is basically, does anyone have any advise on how to proceed?
Am I right about that thing being the switch?  I'd really like to avoid
removing the wrap around all the wiring in the engine compartment.. but
perhaps it is necessary.   Anyone got a wiring diagram for a '57 a-102 with a
BD240 they are willing to share?

By the way.. the wiring back to the lights is ok.. blinkers work, hazards
work,.. its just the brake-lights that don't work.

Thanks -Jeffrey :-)
'58 A-102 Custom Pickup, Grandpa's Farm Truck (got the cattle gates too! talk
about a head turner!)