Wiper help!!! 2012 a4 s-line

I need some help people! My 2012 a4 recently started giving me the "defective wiper" warning every time I start it up. I keep the stalk set on auto/intermittent. Most of the time the wipers work fine. Every once in a while they won't work when I start my car so I flip the wiper stalk through all of its positions and it will usually start right up. A couple of times I had to turn the car off and restart it. Once they are going, I won't have a problem with them again until I turn the car off, even though the warning never goes away and beeps at me about every 10 minutes.

With the car off, both wiper arms move freely while the transmission/motor provides drag that doesn't change tension throughout the entire wiper motion. I believe the wiper arms are resting in their proper place when the car shuts off, and the wipers slide smoothly both up and down when they work.
I am new to the German car market. I have owned mostly Japanese and American cars and have been my own mechanic my entire driving life. I can fix most anything mechanical but don't have much experience with vehicles who are smarter than I am.
To me, from what I have read, it seems that I most likely have an electrical issue? Possibly the wiper relay or the stalk's contacts being dirty? So far, I have popped the hood and removed the cowling, exposing the wiper assembly. When I saw that nothing in there looked like a 70's model gm, I closed the hood and started reading until I found you guys!! My German automobile knowlege is so extensive that I have to ask about the possibility of old worn out wiper blades causing the warning! Mostly what I have read about wiper issues is that the linkage freezes, the motor burns out, or the tranny strips its gears but none of these appear to be the issue at first. I don't have the code reader yet, so I don't have those readings for you to make it easier. Any troubleshooting tips are greatly appreciated!
Thank you for being car nuts like me and helping a ninja out!

My better half took the car to work or I would check the sensor. Do you know if there is a way to check if the windshield has been replaced? I have only owned my car 6 months, so I don't know what has or has not been done...

Tobe said:

If it has auto and only seems to have a problem in that mode it could also be the rain sensor

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Well, the wipers have seized on the passenger side, I believe. I'm gonna pull the linkage in the morning to try to fix it. If I cant, pick n pull is getting a visit! I read another thread where a guy put zerk fittings on the spindles, completely fixing the defect that causes them to rust, corrode and seize. I was hoping it would be a quick relatively inexpensive fix. We will see! Thanks Tobe! Oh yeah, the rain sensor works as well as the automatic light dimming feature. The windshield is audi, but I don't know if it is the original windshield. The rain sensor seems to be attached to the windsheild just fine, without any bubbles or creases in the gel pad. Thanks again!

Thanks Rum! I have spent the last two days pouring over hundreds of posts in various forums. I took the wiper assembly out today and I didn't have any rust! Once I got everything apart, I found the culprit! On the bottom of the spindles there were 2 washers and an o-ring. I live in the PNW, which has a bit of precipitation. The previous owner didn't have a garage and lived in or near Seattle. All this means is that the wipers ran a lot. The two washers had worn down so thin I could bend them with my fingers. Once they were worn, the spindles started wearing a pretty deep hole, like a drill. This created stress, which when combined with the loose as hell linkage, created spots where the linkage bound up and stopped working. No worries, I thought, linkage is cheap. I took the transmission apart to give it some grease love, AND THE GEAR WAS PLASTIC! The metal splines of the motor had worn a deep groove around the entire thing! Gonna go buy a new (used) one tomorrow. I am going to take out the plastic and replace it with something a bit more sturdy. Also, I am going to throw a couple of grease fittings on the spindles for easier maintainance. This should take care of my problem!