Article on The Internet Mini Encyclopædia
Parking motors have a red/light green, brown/light green,
blue/light green and black wire, light green/orange (5 in total) coming out of
the plastic push connector, (black earth, light green/orange permanent ign. fed
line, blue/light green single sweep, red/light green slow, brown/light green
2 trigger for single sweep,
3 trigger for slow,
4 trigger for fast
5 live feed to keep the motor going until the wipers have parked
The park switch is connected by a light-green orange wire from fuse box
terminal 6 (ignition fed) and feeds 12v to the wiper motor so long as the plunger is pushed in(?)
The red light-green wire feeds 12v with a resistor in the main supply lead for slow (I) or..
The Brown light-green wire feeds 12v to the motor for fast speed (II) via a series resistor in the shunt.
I think the mini wiper motor is a permanent magnet motor thus.....
When you turn the wipers off the park switch (in position A) puts power thru to the motor until the switch drops off the track in the plastic cog then the motor has enough momentum to run on until the park switch is set to earth out the motor (position B)...
So the park switch not only disconnects the power to the motor when it is reaching park position but also shorts out the armature of the motor at the same time forcing a current to flow out of the armature, this power is derived from the rotational energy of the armature causing the motor to rapidly decelerate to a standstill
The single wipe switch position can be checked with a multimeter - it keeps the motor winding energised as long as it is depressed - the park (+) feed is independent of any of the functions of the wiper switch on the steering column
There seems to be a wire missing in the mini setup against the classic park and on/off switching set up for a permanent magnet wiper motor - this suggests an earth is established within the body of the park switch from the normally (+) side of the motor when the wipers are at park to stop them dead.
Wipers, Self-parking modification
Coming out of the motor (not the park switch) are 3
Blue - Ground
Red - Slow
Yellow - Fast
These connect on to the back of the park switch and go straight through up to the wiper switch. This leaves 2 wires that come out of the park switch.The actual park switch is basically a change over relay. when the pin is pushed down by the cam on the back of the wiper cog. it switches (not the light green/orange stripe the only one that is left) from the permanent 12V to 0V this shorts the motor out and stops it very quickly. If the motor doesn't stop then this contact is the one that needs attention. When the pin is up (when the wipers are not parked) this lead is connected to the Light green/orange stripe which is the permanent 12V this makes the wipers park when the wiper switch is off.
TO REPAIR PARK SWITCH.
If your wipers either keep going or don't park when switched off then your park switch needs attention. First remove wiper motor from car as described by haynes. Dismantle as per haynes. The bit Hynes doesn't tell you is that there is a small metal clip that attaches the park switch to the motor It is probably hidden under all that grease but if you clean out the motor first you will find it. Slide the clip back and the park switch should come away from the motor. Now you have a choice, you can either go out and buy a new one or take it apart and clean up the contacts. The problem with taking it apart is that you brake it there are small plastic tabs which brake when you open it up.
This will be done shortly to my system. Fit a changeover relay in the park switch circuit so that when the wipers aren't parked the coil in energised and connects o/p from the park switch to 12V unenergised connection of the relay is connected to 0V this takes the load off of the park switch so it will last longer. Once this has been done swap the yellow and Red wires over on the back of the park switch this will give you Fast speed auto park, once wipe and swap the fast and slow on the wiper switch. Well worth doing I think I have been running a similar set-up which works really well. I put the relay in a different place which means that I cannot use slow speed anymore I will convert to the above method when I get some time.
Suspect a lack of lubrication in the coiled flexible wire running between wipers and motor and the drive boxes between wiper and drive wire. Remove the wipers, undo the locking nut around the wiper splined mounting, push the assembly out under the wiper panel, clean out he tubes, grease them and the gear boxes, extract the flexible wire that runs down thetube to the motor, clean that, grease everything and... THEN if it doesn't work think about the bushes. BTW does the motor run with the wipers lifted off the screen?
Wipers, won't park (added 20 Dec 2002)
Problem: Mainly the wiper motor wont park in the correct place.
"it parks, but in the wrong place"
pull out the park switch and see if either the plunger end is worn and/or a track has worn in the cog it rides on. Remove, clean and replace all connections as required.
"if you use the speeds (1 and 2) it works fine. when you knock the lever to the off position, it parks itself where-ever it is"
The park switch is shot.
"is this that famous parking contact that wears out/corrodes or whatever? how easy is it to sort out?"
Pretty simple.. pull the switch out, see if it works when connected but with you playing with it.
Info from Tim
Wiper motor, installation tip
I also refitted the wiper motor today and noticed that a lack of foam underneath it leads to the wires wearing through where they enter the motor body.
Wiper Operation, testing of system ....
Warning, if any of you have the old version of HAYNES, Automobile Electrical and Electronic Systems book by Tranter, the tests for wiper motor parking switch operation on page 188 are wrong. (How unusual for Haynes books!)
The main thing to remember on the Mini, self parking, permanent magnet type wiper motor is that when the park limit switch operates, it not only removes the positive battery supply to the armature, it also then earths this armature brush, effectively shorting it to the other brush. Any back-emf that would be generated if the motor continued to turn by inertia, is thus applied across the motor, quickly bringing it to a halt. The plug has five contacts, which are wired as follows:
Number 1 is horizontal, across one end of the plug and the remainder are vertical, When viewed from the back of the plug, 2 and 4 are on the right-hand side and 3 and 5 on the left.
Pin 1 (Black) is connected to one brush on the motor and also to the
park position contact of the parking switch.
Pin 2 (Brown/Green) is the common, centre pole, of the wiper parking
Pin 3 (Blue/Green) is the high speed brush of the armature, and therefore, if you don't want this function, need not be connected.
Pin 4 (Green/Orange) is the run contact of the parking switch, and the Positive supply to the motor is connected via this pin.
Pin 5 (Red/Grey) is the Negative brush of the motor, and is therefore the Negative (Chassis) connection to the motor.
To test the motor for correct operation, whilst out of the car, an old cable loom with plug attached or the following home made test leads will make the job very easy:
To test normal running, ie to check motor in standard speed:
To test fast speed operation:
To test the self parking operation:
Hope this of help to someone, someday!
(another fantastic tip from Pete Kay, added 20 Dec 2002)
Wiper Motor Donors
Morris Marina! (29 12 02)
Cheers, Neil http://www.theredmini.co.uk
I'm fed up with my windscreen wipers! I replaced them at the weekend because the left one judders like crazy & the new one does it too, any idea why? I wondered if the arm itself could have got twisted at all, meaning it doesn't sit flush to the screen?"
YES, the arms do bend and twist, especialy when you hit them with the bonnet if they are not parked properly!
To correct this, Wiper King Pete Kay has another tip...
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