Question edited for 'year make model' in the correct order.
Question moved to model category.
They all have a bolt with a nut or a screw terminal on the side. Your should have a clamp with bolts as shown in the videos.
You can't bypass it because the immobilizer is controlled by various modules and is there SPECIFICALLY to stop what you are trying to do. You have to fix the problem not find a away around it. In your case, it should be easy. Do the security system reset.
https://www.google.com/search?q=hyundai+i20+security+reset
If the unit is broken, you need a new one, or the old one repaired and fitted by the dealership or an auto-electrician.
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The warning light is telling you there is an electrical problem with the air bag system and you should get the computer scanned for trouble codes. The system is usually disabled when the light is on.
The service and repair manual will provide you all the knowledge you need to fix the problem with pictures and diagram and you will get the manual from the given link https://toolsnyou.com/
It is either under the dash on the passenger side or it is under the hood on the firewall, All the US sold models have the blower under the dash on the passenger side, you may need to remove a "hush" panel under the dash to see it.
