Hi All,

This is a long shot, but does anyone have any information about the wiring for the rear wiper motor on a 9N3? (it's a 55 plate if that matters)

 

Mine hasn't worked for years and I finally got around to looking at it yesterday.  Long story short, there is a small circuit board on the wiper motor that's dead.  I've driven the motor on a bench from a supply and know it works fine, and I've seen with a voltmeter that the car is sending a signal to activate the wiper, and power.

 

I guess I've got three options,

• Replace the whole thing.  Bit loathed to do this as it's only the circuit board that's bad, and I don't have a great history buying car bits.
• Build a circuit to replace the dead bit.
• Ignore it and leave it dead.  (As half of the rear heated window doesn't work it's not a brilliant option)

 

I'm interested in making a replacement circuit as I can do it fairly cheaply, however I don't know what all the pins on the connector do.  There's a 4-pin plug connecting the motor.  Giving the connector pins arbitrary numbers the pin-out is like this,

pin 1 - ground

pin 2 - ???

pin 3 - 12V pulse when turning on the wiper or 12V constant when activating wash pump

pin 4 - 12V constant

 

Does anyone know what 'pin 2' is for, or the kind of signal that is expected here?  I've spent ages on Google and found very little at all, only that it's a signal going to the car computer but no idea what it does.

 

Can anyone help please?

First Welcome to the forum.

 

Pin 2 is a switched ground from the wiper switch it also goes to the pump as the pump spins one way for the front screen wash and the other way for the rear screen 

Wow, thanks for the fast reply and welcome, I didn't expect to get anywhere!

 

Do you know if it's connected to ground when the wiper is in the park position or the opposite?  (the actual switch is closed when the arm is parked, but not sure if it was inverted by the circuit or not).

As you can see it only has a ground when it’s in the “on” or “wash” position and when you select front screen wash it gets +12v 

Ah, I get it now, thanks for posting the diagram.  I'd misunderstood your first reply.

 

Many thanks for your help!