I been having this issue for 3 years now. I have an 03 audi a4 1.8t and whenever the outside air temp goes below 30 degrees my heater blower doesn't work. When the temp goes up like around 50 degrees it starts working. It works all summer with my AC but when it hits winter time it doesn't work. Any Ideas???

 

Have you checked to see if the car is throwing any codes?