Where to catch the Bus from Gongzhufen→ Beijing Capital Airport (Line 4)

Hi, I am planning to take the bus from Gongzhufen→Capital Airport at the earliest time which is 5:10 am from Gongzhufen. Where do I catch the bus? I went today to look at the bus stops going north from Gongzhufen (traffic going north) but none of the stops had 4 written on the signs. Should I catch the bus on the side of the street with traffic going south right in front of Xinxing Hotel?