Hyundai Repair Questions? Ask a Mechanic for Answers ASAP
Because this is a new unit you should not attempt any repairs as this could void your warranty! You have obviously followed the instructions so I would guess there is a fault with the unit.
In this instance you have two options. You can either return the unit to the retailer for replacement or a refund or you can contact Hyundai (Contact Us) for Aftersales Repair and Warranty.
It isn't the fact of the difficulty level of diagnosing the unit that is the problem. With a multi-meter if you can gain access to the switch for instance and the motor assembly you could check the voltage at these points to see if the power is getting through. You could also check continuity of the wiring between the components.
The problem arises if anything should need replacing. You would have voided your warranty by stripping the unit to attempt diagnosis / repair hence the advice to return the unit to the retailer or contact Hyundai using the contact form who could arrange to collect the unit for repair or replacement.