The rear wiper on my P38 is on the blink. It's very sluggish when it wipes. That's if it wipes as often it won't move or it does move then dies stuck halfway across the screen. I have had it operating both with the wiper stalk & with the Nanocom so think that all is good regarding BECM & controls. I think that it points to an issue with the wiper motor. I found a couple of posts on other forums where guys have cleaned up the motor & applied plenty of WD40 to get them going again. At the moment I just try & resist using the rear wiper as I know it will stop mid stroke & hang down until sometime later when it will decide to park hidden away.
What is involved in taking out the wiper motor as I cannot find a guide online?