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Either the switch, or the motor, or perhaps the mechanical linkage, might be at fault and the problem that makes the lift not move.
A: check the switch (and the wires to and from it) for operational status (without power applied, completely unplugged from the power, and with a voltmeter set to Ohms or resistance across the terminals of the switch that is supposed to activate the lift.)
B: check the mechanical linkage, whether it can be moved a little by hand. If it has seized up, is jammed, or needs lubrication, it won't move even if the rest of the lift system is in working condition. Also there might doubtfully be something jamming it in the up position, or a mechanical catch that keeps it up.
C: after those have been verified as OK, the motor might be at fault. Checking on a motor isn't easily done except by a specialist, but removing the motor altogether from the wiring and the linkage, and applying power to it (appropriately, and through the right transformer if a step-down transformer is part of its system) is a good-enough test, before replacing it perhaps.