I have an 04 Cavalier. My fan motor stopped working so I changed the motor but the fan sill isn't coming on. I was thinking maybe it's the temp sensor - If so where would it be located, or what else could possibly be the problem? (also when the a/c is on and I stop at a light the a/c stops working)
If the original motor was bad it may have blown the fuse, check the owners manual to find the fuse box and to determine which fuse powers the fan. If the fuse checks ok the next likely culprit is the resistor that allows the various fan speeds. I believe it is located behind the glovebox in your Cavalier. The next options would be the switch the wiring and your new motor. The A/C most likely stops working at a stop because without the fan there is no airflow. While the car is moving enough air passes thru the system to blow cold air thru the vents. Also look for a ground wire you may have missed while reinstalling the motor.