Message text written by "Dave Terrick"
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If not: by memory, here is what to do:
1. Go to your local electronics store and get a diode (one way valve for
electricity). Ask for something that can take an amp or two. They DO
generate some heat, but only while restricting the current flow - i.e. when
you are using the push/wipe function. (I'm sure somebody who REALLY knows
power will give the spec, I just kinda winged it)
2. Fabricate the "harness. Identify the outgoing power to the washer
pump.
Identify the wire leading to the low speed wiper. Make a jumper wire that
bridges the two lines, with the diode inline.
NB: What is important is that the power be allowed to run from the pump to
the wiper but not from the wiper to the pump. If the diode is backwards,
the reverse will happen and the pump will run whenever the wipers are on!!!
The momentary burst of power to the wipers forces them off park, and then
the park circuit takes over and puts the blades through full
sweep....provided they work, of course. That is the key to this
arrangement - only a short burst of power is needed to do the job.
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If you re-read my post you will notice my exit strategy where I said ther
are other ways to do this...
Seriously, though, This is a clever way of providing a mechanism to
actuate a single sweep operation. I have one reservation, however:
When the wiper switch is in the off position the low speed motor wire
(Red/LightGreen) is connected to the Park Switch wire (Brown/LightGreen)
and when the motor is in the parked position this wire is switched to earth
(this provides dynamic braking to stop the motor and prevent it from
coasting through the park region and continuing on to do another sweep).
Switching another 12 volt source onto this line when the motor is parked
will create a short circuit and the currents are limited by the wire
impedences. This short will be momentary only as enough current will flow
to the motor to cause it to come off of park and the internal switch will
switch to +12 and the sweep will commence. The original (Clear Hooters)
switch on my TR6 would do just this when going over bumps due to an
internal short. The new switch has been problem free for years.
Yes this works but it puts undue stress on the switches, wires, diode and
fuses. If I designed a circuit like this my boss would justifaibly chew me
a new you-know-what and if anybody working for me did this I would do the
same thing to him/her.
So as a person making a living designing circuits and systems I can not
recommend this approach. But the washer switch is a neat idea. I
recommend getting a SPDT relay from Radio Shack (or sim) and implement my
design using the wire from the washer switch to activate the coil of the
relay.
Just trying to be helpfull.
Dave
P.S. Please note that these comments apply to the Two Speed wipers. For
one speed wipers all one need do is switch the park wire to earth.
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