My a/c comes on but my fan does not. I tried moving the setting from auto to on but still nothing. The unit is on the roof. Most of the cooled air is coming down into the hallway leaving the rooms warm.

Check the fan motor. Do you have power to it? Is it very hot? If so motor is bad. Check the capacitor. If it is bulged at top it is bad. If you can soin the fan by hand and it continues to run, the capacitor is bad. If you replace the motor replace the capacitor at same time with the rating stamped on motor.

Check the fan motor. Do you have power to it? Is it very hot? If so motor is bad. Check the capacitor. If it is bulged at top it is bad. If you can soin the fan by hand and it continues to run, the capacitor is bad. If you replace the motor replace the capacitor at same time withe the rating stamped on motor.

Excellent answer with lots of helpful information above!