Green/pink is the accessories circuit and supplies 12v to the homing arc.
Of the other three wires two are the two speeds and the third is from the
homing contact and is connected to the slow-speed wire when the wiper switch
is off. When the switch is on 12v is connected from the switch to the fast
or slow speed wire.
The motor speed *is* controlled by effectively moving one of the commutator
contacts from a position 180 degrees from the other contacts. It is
possible to control speed by adding resistance, but the power dissipated in
it is huge and it is also difficult to select a value that will
simultaneously give a worthwhile reduction in speed on a wet screen and also
not cause the motor to stall and burn out on a dry screen.
You need a relay for each of the speed wires in between the switch and the
motor, but not the wire from the homing contact to the switch.
By now you may have realised that I cannot tell you which wire is which.
PaulH.
http://freespace.virgin.net/paul.hunt1/
-----Original Message-----
From: Ray Wygonik <rwygonik@grove.iup.edu>
To: MG List <mgs@autox.team.net>
Date: 05 April 1999 16:08
Subject: help requested with rewiring wiper circuit
>First thanks for the help with understanding adding relays to various
>circuits. THe web site I was directed to (you know who your are) is
>excellent. I have everything figured out except the wiper circuit. My
>wiring diagram shows 5 wires to the wiper motor. 1. Black-ground wire; 2.
>Green/pink - common to a number of circuits including the washer pump and
>then three other wires coming from the wiper switch. 3. blue/light green;
>4. red/light green and 5. brown/light green.
>
>I need help here. The wiper is supposedly two speed. (I have slow and
>slower).
>Is the speed of the motor changed by tapping on to the motor coil at a
>different location? Don't you change the speed of a DC motor by changing
>resistance? Why three wires from the switch? Do I put a relay in the
>system between each wire of the three wires running from the wiper switch
>controling a direct power connection?
>
>Hopefully my ignorance makes sense to someone. My wiper circuit would
>benefit the most from some good power direct from starter through a relay.
>(fused of course)
>
>
>
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