After Run Water Pump

[sentari]

Ok, so the thing actually works. Well when I connect a battery to it. But why on earth does it never come on when it's connected (the real result is bubbling in the coolant tank after the car is turned off)? What are the possibilities?

So far I tested the fuse and the relay (thanks Bentley!). If I "jumper" the relay it turns on just fine. So something else upstream (coolant temp sensor?) that tells it to turn on is not working right.. The manual is a bit "fuzzy" about the "logic."


MKII TT w/3.2 DSG...