When you need to test a lift chair motor, the first thing you'll want to do is identify the make and model of your chair. Once you have that information, you can contact the manufacturer and request a testing kit. The kit will include instructions on how to properly test the motor.
To test the motor, you'll first want to make sure that it's plugged in and turned on. Then, sit in the chair and press the button that activates the lifting mechanism. If the motor is working properly, the chair should begin to move up smoothly. If there are any issues with movement or noise, then there may be a problem with your motor.
If you're still having trouble after following all of the instructions in your testing kit, then you may need to take your lift chair to a qualified technician for further diagnosis.