Hyundai elantra 2001 central lock - problem
 

Hello to anyone on the forum,
I have a Hyundai Elantra 1.6 2001 and I have a problem with central locking, when you want to lock and key lock on driver's door only and the rest of them will not work because the central interest me where is the central module in the vehicle and what could be a failure and that not central?
Thanks for any response!