Wiper motor continually on

[Alan Johnson]

Afternoon all

Subject covered many times , but still cannot solve it.

Wiper motor DR3A continually on when ignition switched on.

New dash switch , new cover switch on motor , but still works continually even 

turning round cover switch 360 degrees.

Couple of question that have cropped up talking to various people,

Why does live feed to motor go through voltage stabiliser?

I have single speed motor DR3A but a wiring loom for a 2 speed motor DR3

Does both brown/green wire and red/green wire from switch need to be connected to motor?

Seems to work okay with just the brown /green wire connected only, but I have thought to have 

solved it in the garage before only for it to play up when out on the road.

Any advice appreciated

 

Alan

 

[RobH]

It sounds as though the auto-parking contact in the motor is 'made' to earth all the time Alan.  ( Power to the motor should not come through the voltage stabiliser - that is used just as a convenient connection point for switched-live on the power connection to the stabiliser  - B terminal.  The same point also feeds the heater fan and indicators  ) 

The DR3A usually has connection to the self-park switch by the red wire running on the top of the gear housing.  If yours is like this make sure that the connection to the tag isn't also touching the metal body and that it isn't earthing where it exits the motor body. 

 

If you can disconnect the wire from the tag, does the motor stop?  If so there is a problem with the internal switching. 

This is the contact.  The brass plate gets power from the red wire and there is an earth 'wiper' contact on the gear. The motor will run until the wiper gets to the gap when power is cut off.  If the wiper is bent it could be earthing the plate all the time. 

 

If all of this is OK perhaps there is a short to earth inside the motor itself. 

There is another rarer form of the motor with a switch like this :

Again, if the link wire is shorting to earth, or the switch is bent,  the motor will run continuously.

 

The two-speed loom and switch connects earth first to the brown/green wire for fast speed and then to both brown green and red/green together for slow speed so connecting a single-speed motor to brown/green will turn it on for the first switch position. If it was connected to red/green it will turn on in the second switch position. 

 

 

 

 

 

 

Edited March 22 by RobH

[RogerH]

Hi Alan,

 make sure that no body work or bolts from the bonnet rubbers are protruding too far onto the RED wire.

 

Roger 

[Alan Johnson]

Rob

Many thanks for your thoughts.

Have been messing about with it this afternoon and everything seems okay in what you suggest,

but still cannot switch it off.

Going back to my 2 speed wiring loom and I do not know what is happening. Yesterday if I just connected

the brown/green wire it worked okay via dash switch , but today if I connect brown/green wire only it will not work via

dash switch but if I connect just the red/green wire it works.

The motor was a refurbish one and is in  good condition and nothing look amiss , so more head scratching.

[Alan Johnson]

Hi Roger

I have tested motor not connected to wiper cable so more in the open area

and it is still working on its own

[RobH]

This is what is inside, Alan - though in your case the wire to the switch is green/brown.  With no connection to terminal 1 the motor can run continuously if there is an earth getting to the left hand motor brush (LH as drawn that is), so that includes the motor terminal, the link wire, the parking switch and any wires in between. 

[Alan Johnson]

In your diagram Rob you are just showing a single wire going to the switch - green /black,

does that mean that having a single speed motor I only need to connect one of the 2 wires I have

coming from the switch to the motor ?

[RobH]

Yes but it doesn't hurt to connect both in parallel - I added a note about that to the end of my earlier post so perhaps you didn't see it:

3 hours ago, RobH said:

The two-speed loom and switch connects earth first to the brown/green wire for fast speed and then to both brown green and red/green together for slow speed so connecting a single-speed motor to brown/green will turn it on for the first switch position. If it was connected to red/green it will turn on in the second switch position. 

 

Edited March 22 by RobH

[BlueTR3A-5EKT]

How are you connecting the wiring loom to the motor?   The loom wires at the motor terminate in bullet connections.  The single speed motor has Lucar blade connections.   
 

Here’s a trick.   Remove the motor from its installation and isolate it electrically.  Remove the rack so you have the motor and gearbox in your hand.  . Puta towel under it so it cannot short out to the car body.   IE no earth connections anywhere.   Disconnect the motor from the loom and its earth wire and run two wires with Lucar connectors on them to your wiper motor.  Connect them to the wiper motor Lucar terminals.  Now touch them both to the battery terminals and the motor should run.    Remove those connections to the battery.   Now reconnect the motor earth cable to the body.    Touch, one at a time, the wires that go to the motor Lucar terminals to the battery   If you get a flash and the motor does not run reverse the connection.   When no flash touch them both to the two battery terminals and the motor should run.   Disconnect the wire connected to the battery earth terminal, the motor should not stop immediately but run to the ‘parked’ position.   This will prove the internal wiring of the motor and the motor parking switch/cap.    If this tests ok then it is the way the loom or switch or supply is connected that is causing the issue.   
 

The continuous power supply ( green wire) goes to terminal 2.  The switch cable is terminal 1