My 2001 Chrysler 300M is overheating constantly. We think it could be a problem with the fans but we arent sure how the fans work and when they should start/stop spinning.

Yes because it helps cool down the engine.it generates alot heat including the voltage that helps keep it running.so therefore if no airflow is going the engine overheating happens constantly. I just done replacing water pump and thermostat but notice that only one of my fans is working but stopped then i used wd40 both kicked on for ah while and stopped after i tried starting the car again so it could be ah possibly the fan could be but also watch for sensors.