cheerful

The switch is at the 3-dot position, which I think it's the rain-sensor one. Indoor or outdoor, no rain, the wiper will wipe once when the car is switched on. It's cold but definitely no rain or snow. I've cleaned the windshield and wipers as well.

What could be the problem?

Thanks

gfmohn

That's normal. Also, when you change between rain-sensor one and rain-sensor two, it will make a pass, even if it's not raining. If you don't want the wiper to wipe once when the car is switched on, keep it in the "off" position. That's a good idea anyway. I have seen a post where an owner complained that he did what you are doing and eventually his windshield was scratched from airborne dust on the windshield. It must wear out the blades too, when they are wiping dry.

ManiacGT

In auto wiper mode my car does not wipe until rain or mist on the screen. There is no wipe on startup. Perhaps it's a legal/location/regulatory thing.

StanNH

Mine doesn't either. It might just be something as simple as water left on the rain sensor from previous use.

BenzC400

Mine doesn't wipe on start up either. That wouldn't make sense.

kenya

Mine does this quite often as well. I had my windshield replaced recently and thought it might have been related to that since I didn't recall it doing so prior. Not enough of an issue to warrant a special trip to the dealer, but I did i find it interesting that you were experiencing the same (I am presuming you are still using the windshield the car came with).

For clarification...The replacement is an OEM MB windshield direct from dealer service department.

jolt8631

I always leave in Auto and mine never does this. It sounds like, either, a faulty sensor or condensation/dirt in the sensors' opening. If the screen is perfectly clean on the outside, then I'd have it into the dealer.

gfmohn

No, when the windshield is clean, my wipers don't automatically start when left in auto-wipe. But the rest of what I wrote stands.

z28lt1

I know this is an old thread, wanted to see if you (or anyone else) has received more information? I just had my windshield replaced with another MB one, and I now, for the first time ever, get the one wipe at power on. Glass place wants to look at it and attempt to fix, but I'm hopeful to go in with more information. They are speculating dust got in there or something.

Did yours actually work well when it rained?

I'm wondering if disconnecting the sensors during glass replacement, resets it to this functionality, or if I have the wrong window, or what.... I think it should rain tomorrow, so I can at least tell if they are working properly otherwise.

Seems strange that a glass replacement to another OEM windshield would trigger this.