What's the deal with the headlight wash/wipe/intensive clean

[M3KUK]

Hi, trying to troubleshoot my headlight wash/wipe and the intensive clean system. Sorry for the obvious questions but
I need to understand how the system should work from
the Factory.

This is how I understand it works.

If headlights on and you use windscreen wipers a
set number of times(5,10?) the headlight washers
activate, squirting intensive clean fluid on the headlights
and wiping them.

If you push the right hand stalk in, intensive clean of the windscreen is triggered using the little washer bottle.

This is what is actually happening.

Headlight wipers activate as above but Driver's one doesn't
work, no fluid squirted on lights at all. Is there a separate fuse
for each wiper motor? Bentley Manual doesn't tell you.

Pushing the RH Stalk does nothing. I have tested the intensive
clean motor and stalk switch and they are both ok.

Thanks Mike.

[Brianmoooore]

The 'fuses' for the headlamp wiper motors are part of each wiper assembly. They are actually PTC resistors, which heat up, increase their resistance and so limit the current, protecting the motor. They return to their normal resistance when the current is off and they cool down, so are 'self resetting'.
If one works and the other doesn't, it's more than likely that the output shaft of the non working one has seized in the long bush it passes through. Easy enough to strip down, clean, lubricate and reassemble.
The headlamp washers are controlled solely by an internal switch in the wiper motor that has four wires going to it, which, IIRC, is the RH one.

Intensive wash is totally separate from the headlamp washing system, and although the duration of the wash and wiper action is controlled by the wiper module in the fusebox, the washer pump should work if the button on the end of the wiper stalk is pushed in.
Pushing the button 'earths' the brown/grey wire at the switch, which is the same wire connected to the negative terminal of the pump.

The only 'normal' fuse for the entire washing and wiping system at the front of the car is #5, 30A.

[Mr-Lachs]

Really interesting, thanks Both. Have never tried it on my car yet!! Hope you get to the bottom of it Mike. I did put fluid in my intensive tank at the weekend but it just dribbled back out again so there must be a crack (I always did wonder why it was empty ! ), my main reservoir is fine however ... Will need investigation!!

[M3KUK]

Tackled this job today, stripped the right side motor down and found it was rusted to buggery inside.
I cleaned it up best I could, cleaned and lubed the shaft and tried it. Not working, so I reckon it's knackered.
Anyone have one? Also found a second pump on the washer bottle just for the headlight wash.
That's not working either but if wiper motor no good maybe that's stopping it working.
Didn't get anywhere with the intensive wash, that's for another day.

[Brianmoooore]

found a second pump on the washer bottle just for the headlight wash.
That's not working either but if wiper motor no good maybe that's stopping it working.

The headlamp washers are controlled solely by an internal switch in the wiper motor that has four wires going to it, which, IIRC, is the RH one.

You're unlucky to find a badly rusted motor. I've stripped and repaired loads, but have only had to bin one because of rust - the motor case was almost non-existent.

[M3KUK]

I've tested the motor and it has continuity
But is seized up solid! New unit required!

[Brianmoooore]

Both the rotor and the stator of the motor are made of a soft iron laminate, so are easily rusted together, and the slightest bit of rust on them will seize the motor.
Short answer is, try to get it apart - you've nothing to lose. Be careful not to damage the carbon brushes.

[M3KUK]

Sourced a replacement motor, fitted it today and all is well again!
Thanks for the help.