I know this is an old thread, I hope you have figured it out. You may want to google "hyundai-entrant-tail-light-assembly-replacement" you may find a site name youcanic or something. I believed I used that site to fix my one of my elantra problem.04 GT, A few days back my air bag light turned on and red, and stayed red. It flashed a few times first. Now its always on.
I didnt really care much at first, but now I noticed that the horn doesn't work when I press the steering wheel. So I'm wondering if theres any quick fix or way to figure out what might be going on without going to the $100.hr ripoff joints. I'm mainly concerned about the horn.