Rear window wiper wiring on a Nissan MQ/MK

[David_S]

I have just replaced a broken rear window on my old MQ. Replacement was off a turbo diesel and came with a rear wiper. Does anyone have a wiring diagram which shows how it is wired up? My Nissan Service Manual was printed in June 83 and does not show it.

There is a 4 pin plug on the unit. Black is earthed, a blue lead goes to the motor, blue with red stripe comes from the motor and goes to an insulated terminal block (reversing switch?) and from there back to the plug. A yellow goes from another terminal on the insulated block back to the plug.

I have tried hooking it up with various combinations to a 24V battery but can't get any reaction which either shows I don't know what I am doing (probable) or the motor is stuffed

It would be nice to get it going as otherwise I will have to plug the holes!

Another question. It is a 24V wiper and my truck is 12V. Would it run (slowly) off 12 V or will I have to change the motor or rewind it?

David

[David_S]

I think I have sorted it out. The insulated terminal block is a parking switch to make sure the wiper stops at the top of its stroke. The reversing of the wiper is achieved mechanically through a simple crankshaft action.

Does this diagram look right?




And the motor does run (but at half speed) on 12V. Any suggestions on improving this?

Not sure if it is worth the effort to wire up though. And the window demister probably won't heat up much on 12V either.

David

[David_S]

Well the above circuit would have worked if the unit had been wired like that - unfortunately it isn't as I found out when bench testing and could not get the unit to park

I think (hope) that this time I have got it sorted. The unit's parking switch is a 2-way switch wired as in the revised diagram below. This bench tests OK though why Nissan wires it this way I don't know. It is similar to the front wiper unit.



Hope it works in situ

David