No brake lights - 62 Falcon

Can anyone give me some ideas as to what would cause the brake lights to
suddenly quit working on a 62 Falcon. There is no fuse for the brakes in
the fuse box and I don't have an electrical schematic for the car. I
checked the switch on the master cylinder and it's working good. The green
wire that comes in through the firewall from the master cylinder brake
switch has good 12v when I press the brakes at the last point I can check it
at, before it goes up the steering column. The turn signals work great! So
I know the wires going to the back of the car have to be good. Can the turn
signal SWITCH malfunction is such a way as to allow the signals to still
work, but not the brake lights? I'd appreciate any ideas, or even a copy of
the wiring schematic for a 62 Falcon, if someone has a scanner or can part
with a copy.

Thanks in advance.

John

John Derickson wrote:
>
> Can the turn
> signal SWITCH malfunction is such a way as to allow the signals to still
> work, but not the brake lights?

You've got it. I no longer have a schematic, but the way the turn signal switch
works, the power for the turn signals comes into the switch. So does the output
from the brake light switch on the master cylinder. If you hit the brakes and
neither signal is on, the power from the brake light switch goes directly to
both brake lights. If one of the turn signals is on, power from the brake light
switch is disconnected from that side and power from the flasher is connected
to that brake light. This is accomplished by the lever sliding two contacts from
side to side.

IIRC, the entire switching arrangement is in the steering column and is simple
enough that it might be possible to fix the problem without replacing anything.

Schematic is something like this -

______ ______
| | | | | |
F BL MC MC BL F

Here, the left turn signal is on. "F" is flasher, "Bl" is brake light, "MC" is
master cylinder.

______ ______
| | | | | |
F BL MC MC BL F

Here, neither signal is on.

______ ______
| | | | | |
F BL MC MC BL F

Here, the right signal is on.

George Patterson
To a pilot, altitude is like money - it is possible that having too much
could prove embarassing, but having too little is always fatal.

Thanks George,

You confirmed my suspicions. Since I know that power is arriving from the
master cylinder to the last coupling before going up the steering column, I
guess my next step would be to pull the steering wheel and check at the
connection on the turn signal switch to see that power is arriving there
with the brake depressed. I already know that the wires going to the brake
lights from the turn signal switch are good, because the brake lights use
the same wires, be it turn indicator or just plain old brake light. What I
was having a hard time doing ... was figuring out exactly how the flasher
played into this whole thing. LOL I'm not a real little guy, and at one
point I thought I was going to spend the rest of the afternoon up under the
dash. Anyway, I ran out of time yesterday, so I guess I'll do the steering
wheel thing today. After reading your reply this morning, I went and found
two sources for a "turn signal switch", as I think that's what it will turn
out to be. I was actually surprised that there is no fuse for that brake
light wire coming in from the master cylinder. Maybe the turn signal switch
is designed to burn up in the event of a short. LOL

Thanks again for you explanation.

John

Could there be a fusible link in there? Its just a short piece of finer
gauge wire. The idea is that the fusible link will melt like a fuse
rather than melting the whole wiring harness.

John Derickson wrote:
>
> Thanks George,
>
> You confirmed my suspicions. Since I know that power is arriving from the
> master cylinder to the last coupling before going up the steering column, I
> guess my next step would be to pull the steering wheel and check at the
> connection on the turn signal switch to see that power is arriving there
> with the brake depressed. I already know that the wires going to the brake
> lights from the turn signal switch are good, because the brake lights use
> the same wires, be it turn indicator or just plain old brake light. What I
> was having a hard time doing ... was figuring out exactly how the flasher
> played into this whole thing. LOL I'm not a real little guy, and at one
> point I thought I was going to spend the rest of the afternoon up under the
> dash. Anyway, I ran out of time yesterday, so I guess I'll do the steering
> wheel thing today. After reading your reply this morning, I went and found
> two sources for a "turn signal switch", as I think that's what it will turn
> out to be. I was actually surprised that there is no fuse for that brake
> light wire coming in from the master cylinder. Maybe the turn signal switch
> is designed to burn up in the event of a short. LOL
>
> Thanks again for you explanation.
>
> John

--
Eugene Blanchard
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John Derickson wrote:
>
> Can anyone give me some ideas as to what would cause the brake lights to
> suddenly quit working on a 62 Falcon.

One other thing. If you're going to be working on this car, it would be handy
to pick up a copy of Glen's Auto Manual. It only covers something like '56 to
'65, and is long out of print, but it's far superior to Chilton's. Run down a
copy at http://www.bookfinder.com .

George Patterson
To a pilot, altitude is like money - it is possible that having too much
could prove embarassing, but having too little is always fatal.