AudiForums.com - Windshield vipers not pumping fluid all the time. It only pumps when it like it

I have 2001 Audi A6 Q 2.8L 30V. Recently I was using the windshield viper and was trying to pump out the washer fluid but the fluid wasn't coming out. This was in early morning. After that I tried cleaning the windshield again around noon time and it worked for 3-4 times and then the water started coming in such a way that it looked like that there was no pressure. Just a small splash after first 3-4 successful splashes.

Basically, the motor is pumping the fluid intermittently. It works whenever it likes and stops whenever it likes. There is no specific time that it stops working. Specially, first thing in the morning it never works. It almost feels like that the washer pipe froze and it has to wait for 5 hrs to start working again. Audi has heated channel for windshield washer so I doubt that the channel freezes on me. I live in New England and in winter it is a huge problem for me.

Anybody.... please help me on this issue and if there is anything that I can replace it at home or troubleshoot at home, it will be helpful. Since stealer costs much more, I won't go to them. I want to try it myself first and then if nothing happens, I will go to some regular mechanic.
Any pictorial description of how to repair or troubleshoot would be appreciated. Thanks again.

K