I have never had to take a written test for my Thai license. The last time I renewed my 5 year license I had to watch a 45 minute video. The video did have some review questions in it but I never had to answer them. This was about 2 years ago. Just have to do the vision and reflex tests.
For Thai's, like my wife, they now have an online course/test they have to take and pass before going in to get the actual renewal.