1997 Plymouth Voyager cooling fans

Engine Cooling problem
1997 Plymouth Voyager 6 cyl Front Wheel Drive Automatic

Cooling fans not operating when temperature demands them to operate. Unable to locate the cooling fan relay if listed as cooling fan relay. If listed by another name I don't know which one. With motor off, I have probed the wires going to the fan and get nothing when test light is hooked to ground. If hooked to positive and probe wires, test light comes on on both wires. With motor running, and temperature up, I still get no power to either wire going to fan. Is there a way to test the fans to see if they are good or not? They do free-spin with motor off. Any ideas to help me solve this problem will be greatly appreciated.