I have a 2001 Neon and I just replaced the radiator. After running the car for a while, the fan never comes on. I tried checking the connection to the fan that gives it power and it seems intact and connects all the way. I checked the fan relay and when the contact inside the relay touches the fan still doesn't come on. The fan worked fine before changing the radiator. I feel like I'm running out of options and I need some help please! Thank you!

 

I would first check the fuse. Next I would look at the electrical connecter closely. Anything bent or broken. Make sure contacts are clean. If it looks good you can try warming up the car and check for voltage from the contacts at a point where the car is warm enough and fan should kick in. Since the car is running you have to be very careful. If the car is hot enough you might be able to kill it and just turn the ignition on to get a reading. I believe you should be getting 12 volts. If no voltage I would check the relay next. If you are getting voltage I would suspect the fan is shot.
good luck