Is it possible to adjust the frequency of operation as in light drizzle my wipers operate pretty much continuously.
I have checked in the handbook but cannot find any reference to adjusting the speed.
Thanks in anticipation
As far as I know, no there isn't.
Assuming you have a rainsensor then the only remedy is to keep that area on the windscreen absolutely spotless, and even then the wipers seem to lead a live of their own.
Other option is to use something like this http://www.amazon.co.uk/OMBRELLO-GLASS-TREATMENT-APPLICATOR-9ml/dp/B005JDDD4S
Had it done, just to give it a try, on mine. To my surprise, this was something that really works! Rain gets blown off, improved visibility and the rain sensing wipers now work as they should work. They only wipe when they need to wipe.
The Rainsensor feature does seem to make erratic decisions sometimes about how frequently to activate the wipers. I use Griot's Garage Glass Cleaning Clay and machine polish for the glass to get it really clean and smooth, and finish up with their Glass Sealant...which is like Rain-X. Having done all this, I then avoid driving the car in the rain because it makes the undercarriage filthy...
I'm sure someone will jump in but I recall reading that the rain sensor sensitivity can be adjusted by the dealer or someone that can access STAR.
I find my wipers a bit sensitive too and what really makes me crazy is when the wipers speed up and wipe really fast. It's fine when I get hit by a huge unexpected splash when a car ahead hits a big puddle, but not when it isn't raining that much. Overall, I'm very happy with the auto wiper feature.
I don't use it. They just go crazy fast with little rain. I use my manual intermittent wiper setting. I just push the one wipe button. Sometimes I use voice command; I say wipe before my finger pushes the one wipe button. Works great all the time. :wink:
I have had this issue in the past with them wiping unnecessarily when little or next to any water on the screen. It drives me crazy. I applied Rain X thinking it would improve the situation but it seemed to make it worse. Since then it seems to have got better as the Rain X has 'worn off' ie. wipes less often than it did but still too often for my liking. Though you do need to take into account that at night you don't want it to wipe too slowly as it can be dangerous. I had auto wipers on my previous car (not a Merc) and that was the same but I found that when I fitted new wiper blades it did get a lot better. Given the choice I would prefer a timer rather than an auto sensor any day. I have read on this site that it can be adjusted by a dealer but not sure if it can be or not.