On some floor plans, the motor is under the bed and the bed top platform has to be removed to get to the mechanism. On others, it may be behind the fascia above the headboard and that would have to come down.
If the motor is not making any noise, it may be an electrical problem. If the switch has power and the switch is electrically ok, you may have a bad connection under the bed.
If the motor is turning but nothing moves, you may have a problem with the chains or cables driven by the motor. In that case, manually operating the motor won't help. You have to take things apart and repair the mechanism.
If the motor is quiet, I would check the power to the motor first.