If your treadmill is not working properly, you might have a problem with the motor. You can test the motor yourself to narrow the list of potential problems. Testing a treadmill motor is a relatively simple process.
Unplug the treadmill from its electrical outlet.
Remove the treadmill’s plastic housing to expose the motor. Remove the screws on each side of the housing and pull the housing off the frame of the treadmill. Refer to your treadmill’s manual for instructions regarding the location of the motor and any special requirements for removal of the housing.
Detach the motor’s lead wires from the power supply. Although the lead wires usually consist of one red and one black wire, they are different colors on some makes of treadmill. You can locate the lead wires by determining where the motor attaches to the power supply. The power supply is the place where the external power cord connects to the inner components of the treadmill; the lead wires are the two wires connecting the motor to the power supply. Loosen the screws connecting the lead wires to the power supply and pull the ends of the lead wires off the connection points.
Press the tip of each lead wire to the positive and negative connectors on a fully charged cordless drill battery, car battery or lantern battery. If the motor is in working condition, it will cause the belt to turn at a low speed as long as the lead wires stay connected to the battery. It does not matter if you connect the positive and negative lead wires to the battery in reverse order; this will simply cause the motor to run backwards, moving the belt in reverse. If the lead wires are connected to a fully charged battery and the motor still does not run, your motor is defective and must be replaced.
Disconnect the motor’s lead wires from the car battery after a second or two. Car batteries have a high amperage that can burn out a treadmill motor if connected for too long.