Odd that it shuts off when the probe is shorted and at -15c. I'm confused, is the evaporator submerged in coolant or did you just put the rad up against the evaporator (cold thingy on the a/c)?
At any rate, here's our buddy Gutter'z v.2 Chiller action:
http://www.overclockaholics.com/foru...ead.php?t=1218