My 2014's intermittent wipe has started to behave oddly.  Single wipe, normal and double speed are fine.  If you switch to intermittent (it has automatic wipers as well) it starts off with a normal single sweep but then rapidly (less than a second) moves to normal and then double speed constant.  This is not dependent on the amount of water on the screen and changing the interval with the stalk control makes no difference.

I tried cleaning the windscreen over the sensor rather aggressively with matal polish, in case my habit of using a polymerising wax had built up some for of film over it.  No change.

My thoughts are: wiring issue; connection corrosion; BCM problem.

Anyone have any other thoughts?

Hmm, tricky. Sounds like the sort of thing a faulty capacity could cause.

It's possible that the issue could be with the rain sensor itself. The rain sensor may be faulty, causing it to misread the amount of water on the windshield and switch between speeds incorrectly?

 

I have no idea.  It behaved correctly for a few minutes the other day - working at an intermittent rate until I changed the rate with the adjuster on the wiper stalk.  Then it went haywire again.  Think I'll try a new wiper stalk first, then build up to the most expensive parts.  That's after I give the wiring a good looking at, once the weather improves.

Happy new King, everyone!

On a 2014 car it's worth plugging in diagnostics to see if that offers any clues before throwing parts at it

I think I may have solved it.  Installed new wiper blades (well) before the issue arose and I noticed that the lengths were swapped.  Longer one on driver's side, shorter on passenger.  It was the other way round previously.  I was happy, as it wiped higher up the screen when I was driving so I didn't need to retract my neck to see clearly.

I noticed yesterday, though, that the wipers now appear to bypass the wiper sensor, which is in the area adjacent to the mirror mount.  Swapped them over and the sensor is now wiped.  Not been out in any intermittent rain to test yet but I am hopeful that it has sorted the issue.  Should have realised that it was something I did.

The (Bosch) wipers were installed as per the instructions on the box, so this may be a heads-up for others.  Longer wiper on the passenger side.

Definitely sorted.