so the fan works but blows cold? and clicking in the dash right? do you hear the clicking only when you work the temp controls or all the time? and your not running hot or overheating or under cooling? temp gauge is ok?
i would start with bleeding the system, if that fails it could be a actuator has a cracked gear in it, is it both sides are blowing cold?
if you remove a actuator and turn the knob manually and get heat, you found your problem.
heres a ling to how to remove them little buggers.
http://www.grandprixforums.net/blend...ent-21941.html
you could also lift the carpet to see if its getting wet under it to rule out the core leaking.
and check you lim bolts for wetness, the bolts could be leaking. thats where my coolant was leaking from. i was loosing like 2 cups a week, not much but enough to notice it was missing. a flashlight in broad daylight will help see down there on the back side better.