The light is probably on because there is no air bag installed. It probably deployed in accident and was never replaced.
Any mechanic with a scan tool can check the issue for you, does not have to be a dealership.
First you need to make sure there is actually an air bag installed in the car....it is not uncommon for people to not replace them, as they are very expensive.
Then if there is one installed, goto a good mechanic and have him hook his scan tool to it and check the codes, that is the only way you will be able to find the source of the problems. And dont go to your local auto parts store for them to check the codes...they cant check air bag or ABS code, only engine codes.
And stay away from the internet reset scam. Best stay with a local mechanic that you can goto for a problem.
Lastly...DONT TRY TO MESS WITH THE AIRBAG SYSTEM IF YOUR NOT TRAINED....MANY PEOPLE EASCH YEAR GET INJURED SERIOUSLY (AND SOME KILLED) BY IMPROPERLY WORKING ON THE AIR BAG SYSTEM...yes you can get killed by an airbag!!!!!
You are best to take it to a mechanic if you dont know how to work on it...and no offense, but your questions show that you have no experience or training in this area. Btw, I’m available to help over the phone in case u need at
https://www.6ya.com/expert/sean_54c3a3dc48a7773c