So basically, everything is known good except for the PCM? I'm with Master Tech on this one, time for a scan tool.

 

with the car running, unplug the Coolant temp sensor. It should throw the PCM into default mode and command the fan ON. if that doesnt work, then I am with Master Tech on this one.

 

I have a 2005 Grand Caravan. the check engine light came on. I scanned it and found the Fan Circuit 1 fault. # P0480. I checked under the hood and found the power plug to the fan on the driver's side of the rad unplugged. I plugged it in and cleared the code. the next day it was back. Checking further i found the relay for the fan (Behind the grille). I checked the fuse which was good. I unplugged the coolant temp sensor. and the fans do not come on. I unplugged the the relay and jumped the contacts in the plug and both fans came on. When the relay is plugged in nothing works. I performed some tests and found there is no signal coming from the ECU. Any suggestions?

 

Pretty common for the relay to crap out. It is held on with a rivet so get one of those as well if you replace it.