Ed and Marc,
It turns out that my wiper switch explanation may not apply to your
car. My cars are late cars and at least the one I'm most familiar
with is not wired the way it shows in the schematic. The switch in
the schematic is quite unusual but could be reproduced by a double a
double pole, double throw (DPDT) switch with the center contacts tied
together. I've noticed several things in the schematics for these
cars are incorrect. The fact that the wiper switch is labeled as the
reverse lamp switch in the large schematic is only one of several
errors that I encountered in that schematic.
Ed,
What Amphicar was doing with the wiring shown in the schematic was to
ground the motor when the internal switch hit the park position.
This grounding acts like a brake to the motor to achieve a quicker
stop action. I don't know how many cars were wired with this
configuration. Like many things with these cars, sometimes you just
have to figure out what you have and how to handle it.
John Friese
67 White
67 Red
--- In amphicar-lovers@yahoogroups.com, "WB6WSN" <wb6wsn@c...> wrote:
>
> ----- Original Message -----
> From: John Friese
> To: amphicar-lovers@yahoogroups.com
> Sent: Saturday, September 11, 2004 5:01 PM
> Subject: [amphicar-lovers] Re: Wiper Switch
>
>
> Marc,
>
> First the horn. The horn gets 12 volts continuously from the
battery
> and seeks a ground return path to activate the horn. It gets
this
> return path through the horn button which connects the horn wire
to
> the metal steering wheel shaft. For some reason, one thing that
is
> pretty common to horn problems is a hard build-up of crud on the
> contacts inside the horn. The horn is pretty easy to open up and
> cleaning those two contact points might just fix that problem.
>
> The wiper is a bit more complex a problem. There are three wires
to
> the switch. One is the 12 volt source, the other two run to the
> wiper motor and supply power either directly to the wiper motor
or
> indirectly to the motor through an internal switch inside the
motor
> assembly. When you turn the wiper switch on it sends power
directly
> to the motor. When you turn the wiper switch off the power is
> redirected to the motor through the internal switch inside the
> motor. Therefore when you turn the power off the wiper will
continue
> to run until the internal switch opens and stops the motor. This
> internal switch is positioned so that the wipers come to rest at
the
> bottom of their cycle.
>
> The panel switch used for the wipers is electrically called
a "single
> pole, double throw switch" and is quite common. You should be
able
> to find some other switch that has this configuration and will
make
> your wipers work normally.
>
> John Friese
> 67 White
> 67 Red
>
>
>
> John:
>
> When I was stripping my car down, my wiper switch was in such bad
shape that I didn't save it. However, when I look at the Amphi
schematic (the big plastic laminated one), I see that Switch 29 is
actually a Double Pole Single Throw (DPST) switch. In the Wipers OFF
position, the Brown wire from the wiper motor is grounded. When the
switch is activated, the Brown wire is not connected to anything
anymore. However, the Red/Black wire from the wiper motor is now
connected to Fuse 4, which in turn is fed power from the ignition
switch.
>
> Anyway, the two movable contacts (the poles) are jumpered together,
making the switch act as a "shorting bar" in each of the "throw"
positions.
>
> From the schematic, I can't tell why the Brown lead needs to be
grounded in the Off position. It would have been clearer if there was
some electrical detail shown within the symbol for the wiper motor.
>
> BTW, the schematic creates some confusion, with two separate
switches labeled "Switch 29." The left Switch 29 is clearly not
the "Reverse Lamp Switch", but is properly the "Windshield Wiper
Control Switch." To the right of Switch 27 is the correct Reverse
Lamp Switch.
>
> Ed
> El Cajon, CA USA
> 67 Rust Guppy
>
>
> [Non-text portions of this message have been removed]
