Where can i find the coolant temperature sensor on a 2004 audi a4?

I need to replace my coolant temperature sensor and i cant find it anywhere. the dealer is trying to charge me $200 bucks to try to replace something as easy as this...anybody got a 2004 Audi 1.8 V6 A4?|||try ebay or craigslist. i know the audi dealer charges so much for repairs.|||What engine? You said it has a 1.8l V6. It can't be a 1.8l %26amp; a V6. The V6 is 3.0l. Anyway.... The 1.8l is at the rear of the cylinder head a few inches below the valve cover gasket %26amp; the 3.0l is located at the rear of the passenger side cylinder head. Both have a 4 pin connector plugged into them. if you change it yourself be sure to put only Audi coolant in it. YOU can prob. only get it online or at Audi.