A 'flick-wipe' needs to be connected differently according to whether you
have the single-speed or early two-speed wipers on the one hand, or the
later two-speed wipers on the other.
For the one-speed connect a make contact between ground and the black-green
i.e. at the existing wiper switch. If you hold the flick-wipe switch
operated long enough for the motor to get into its homing arc it will park
on its own.
For the early two-speed (some 1964 to 1967 models), identified by there
being black, black-green and light-green wires at the existing switch and
motor, plus a green at the motor, the connection of the flick-wipe switch is
the same as for the one-speed.
For the later two-speed wipers, identified by there being green,
brown/light-green, blue/light-green and red/light-green wires at the
existing switch and motor, plus a black at the motor, the requirements are
significantly different due to the different homing circuitry of this motor.
In this case a change-over switch, or a make switch operating a change-over
relay, is required. The break contact *must* break the brown/light-green
between the existing switch and the motor before connecting green to the
half of this wire that goes to the existing switch. If the green is
connected to the half that goes to the motor it will blow the green fuse.
This is because the 'homing arc' on the two-speed motor is itself a
change-over switch that effectively connects 12v to the slow-speed winding
while the wipers are 'off park', then switches over to apply a ground to the
slow-speed winding when the wipers reach their park position. This
instantly stops the motor and allows the wipers to park in a more
predictable position than the early types, which just disconnect 12v from
the motor when it reaches park. In this case the motor doesn't stop
instantly but 'winds down' due to inertia, which means the actual park
position varies according to how wet or dry the screen is, more so than the
later system, at any rate.
Schematics for all three types, plus other circuits in the MGB, can be found
on the web site below, select 'Spanners', 'Electrics' and 'Schematics' for a
list.
PaulH.
http://freespace.virgin.net/paul.hunt1/
(or if that URL doesn't work try )
(http://194.168.54.52/paul.hunt1 )
----- Original Message -----
From: David Hill <davhill@cwcom.net>
To: MG List <mgs@autox.team.net>
Cc: <triumphs@autox.team.net>
Sent: Tuesday, January 04, 2000 10:44 PM
Subject: Flick Wipe
> Hi, All.
>
> Anyone out there seriously clued up on electrics?
>
> In the muck and filth of winter, it would be really nice to have a flick
> wipe facility on both my classics (standard Lucas 2-speed wipers).
>
> I vaguely recall from the '70s that this was possible by putting in an
> additional feed to the wiper motor, via a momentary contact switch. The
> idea was that the wipers would wipe once when the switch was pressed, then
> park again.
>
> Question: can this work and if so, which wire should be energised via the
> switch?
>
> Thanks,
>
> Dave Hill
>
> David Hill/Psychomotor
> Can I Telework for you? Try...
> http://www.angelfire.com/biz4/davtel/index.html
> Can I help you? Try...
> http://www.angelfire.com/de/ukphobias/index.html
>
>
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