06 Hyundai tib passenger door lock not working

SOURCE: Door locks don't work

Disassemble the paneling on left side ,under the steering wheel. Remove all screws and pull out the panel until you can you can reach behind it to remove the two Black Relays, on the side closest to Steering wheel. Remove the Relay covers, Clean the contacts with a 1/8 fine strip of 600 wet/dry sand paper. Only place the paper between the contacts, and pull out while holding slight pressure on the relay Armature. Turn over the sandpaper and repeat once again. Very gently press the TOP resting contact pad closer to the armature, to lessen the gap between the contact points, so the armature doesn't have to travel as far to reach the closed contact position. Repeat the above with the other2nd Relay. Replace the covers, reinstall the relays And test the Door locks prior to buttoning up the paneling. Note, a pair of long needle nosed pliers will help in removing the relays. Just Grip the relay and rock in Forward and Backward as you apply upward pressure.

SOURCE: 2003 Hyundai Sonata Door Lock Problem

I had this problem. Through some research and asking some service personnel I found out it is a fairly easy fix. You will need to buy a new relay switch for the door locks. The dealer will/should know what you need. They are located (two of them, buy two and replace both) on the back side of the fuse box. It is not that easy to get back there. I had to lay on my back with my head up under the instrument panel. They are visible and can be removed if you take some time and be careful. Once I knew what I was looking at, it was easy to replace and the remote works like a charm. You can go to an auto supply, like Autozone, and they should have a schematic to show you where these relays are.