Wiper not wiping

[Stoned]

I think I asked this before without a answer soooo

Basically when I switch on my rear wiper it does whatever it wants to do. It usually wipes about halfway across the window and then stops, it then proceeds about another 3rd putting it a little way into it's return stroke before stopping and so on and so forth

End result is it no longer goes back and forth in one movement like it used too. In fact to even get a full stroke AND get the wiper to rest either at the top or the bottom I have to cycle the button multiple times and guess when to turn it off all of which is extreemly irritating

Anyone got any ideas why?

How does the rear wiper sense it's done a full movement as mine seems clueless

 

[Fast Guy]

Possibly the brushes on the motor are worn and need replacing? (or a new motor) or something is loose:- retaining nut, worn splines?

 

[Stoned]

Well to add some additional mystery it does exactly the same thing without the wiper arm on it at all, i.e. wipes small, random amounts and...
also it wipers back and forth perfectly when you hold down the rear window wash option for as long as you hold it - which would lead me to believe the motor works just fine...

 

[Fast Guy]

It would lead me to believe that too So it could be a dodgy switch/wiring or control unit (if there is one)

 

[Stoned]

A friend suggested a faulty relay. Does anyone know where the rear wiper relay can be found, in the glove compartment or in the engine bay?

 

[Fast Guy]

There's a rear wiper amplifier which should be next to the indicator flasher unit. Can't quite tell from the picture but it's either in the steering column somewhere or behind the dash in front of your left knee somewhere.
The relay is in the engine bay, it should be the 2nd from the front in the box by the power steering reservoir.