Did you try changing the flasher unit on the fuse box ? Sounds like that may be it.
The turn signal flasher is combined with the hazzard switch. It is connected to the back of the hazzard switch.
Check fuse and/or flasher
The airbag warning signal might flash on the Hyundai Sonata dashboard if the component is malfunctioning. It should be checked by a mechanic.
it is part of the hazzard light switch on the dash under the raido
On my 2000 Forester, the dashboard illumination dimmer control is on the turn signal stalk. --Ken
bad wiring in your steering column to the hand control?
It's right behind the hazzard button, you must pry the button out for access.
The hazzard light switch on the dash to the right of the speedometer is also the turn signal flasher. This is a common part to fail if intermittant turn signal operation. - TechJK -----------------------------
I may be slightly off, but I have noticed the 'click' for the flasher is coming from the hazzard flasher button. I have removed the harness and found the turn signals do not work as long as the switch is disconnected. Hope this helps!! Just replaced mine. The Emergency Flasher switch (button) on the dashboard serves as the turn signal flasher also. Around a $35.00 item. You have to disassemble the face of the dashboard.. relatively easy, about 45 minutes.
under the dashboard on the driversside
Many mistake the hazzard flasher for the turn signal flasher. Maybe you replaced the hazzard flasher? Also, a burned out bulb will not give enough electrical resistance to the circuit, and result in a very slow or stopped flash. Since your flasher is most likely mechanical, turn on your hazzards and put your fingers over the flasher unit. If you feel it click on & off, then you need to find the turn signal flasher.. because you are touching the hazzard flasher.
The AT check signal light means that there is something is wrong with the transmission. A slipping transmission can be the cause of this.