How to Troubleshoot an Oil Furnace Blower Motor

Turn off the power to the furnace.

Spin the motor manually to check whether or not it spins. If it does not spin or appears hard to spin, check to see if there are oil ports where you can add oil. If the motor still does not spin or spins reluctantly after adding oil, you should replace the motor.

Check the wires connected to the motor to ensure they are connected properly and securely. Replace any worn wires.

Test the run capacitor. The run capacitor holds the electrical charge used by the blower motor. The side of the run capacitor will generally give the ratings for the unit. A reading outside the listed ratings means the capacitor needs to be replaced. Use a volt ohm meter to test the capacitor by connecting the wires from the meter to both posts on the capacitor and setting the meter to the capacitor setting. If the meter gives you a reading outside the ratings guidelines, the capacitor is bad.