Front Windscreen Wiper Failure 2013 XF Sportbrake 2.2TD Portfolio (200BHP)

[B17FLYBOY]

I have searched and searched online and whilst I can find lots of posts about wipers not parking properly, I cannot find anything that resembles the fault I have at the moment and I am seeking advice please!

The first symptoms started a couple of months ago; on odd occasions the front wipers failed to operate at all, or sometimes would wipe normally for a couple of minutes then stop working. There was no 'slowing' of the wipers leading me to believe nothing was binding. Washers worked as expected. More often than not pulling over and switching the ignition off for a couple of minutes before starting again would cure it and wipers would operate normally. I would then go days or weeks with them operating normally before the problem would recurr. Rear wiper has always worked as it should.

However, a couple of weeks ago the wipers did one sweep, parked in the correct position, stopped, and have never worked since. Due to occasional "chirping" and the very occasional "parking brake failed to operate" I suspected battery problems as I have read extensively that strange gremlins creep in off the back of this, so I have replaced both the main and auxilliary batteries a few days ago but this has not resolved the wiper issue.

I have checked the wiper fuse and that is fine. I cannot identify which relay (or relays - I believe there are two) that operate the front wipers to check those - if anyone can tell me which relays these are I would appreciate it as I can check/swap these out.

At the weekend I removed the plastic trim at the bottom of the windscreen and removed the wiper motor. I put a volt meter across different pin combinations and switched the wipers on. The voltage was constantly pulsing but I got the following approximate readings (+ve terminal on pin 3 of wiper connector and -ve terminal on pin 2):

Wipers on intermittent - voltage pulsed between 1.4 and 2.9V
Wipers on Steady slow - pulsed between 1.3 and 2V
Wipers on fast - pulsed bwteen 0.9 and 1.3V
I could not read any voltage on any other pin combinations (1-2, 1-3, 1-4, 2-4)

I am not sure if these figures are accurate as a voltmeter does not read fluctuating voltages very easily. However, if they are correct I don't imagine this is supplying enough voltage to operate the motor so the fault may be further down the line?

Can anyone shed any light on what might be at fault here?

Should I try replacing the control stalk/switch for the wipers, or perhaps the wiper motor itself? Relay(s)?

I love my Jag but this is really frustrating the hell out of me!

Any help really appreciated!

Thanks!

[Jimbov8]

There is a known issue with water from the windscreen washer pump wicking into the electrics, specifically causing corrosion in the Central Junction Box/fuse panel in the drivers footwell, which can result in all kinds of electrical issues. There is an updated washer pump and wiring as a fix but it is not a cheap job so worth checking for signs of water ingress and corrosion in the said panel. There is plenty of info about this if you do a Google search.

Worth a look.