One problem related to hazard flashing warning light unit has been reported for the 2004 Hyundai Sonata. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Hyundai Sonata based on all problems reported for the 2004 Sonata.
Emergency flashers began flashing for no apparent reason and would not be turned off. Then trying to use the keyless entry door opener, the locks began locking and unlocking. When the car was running this stopped. We took it to the dealer and they replaced the etac module, then the entire fuse box. After returning home, the hazard lights again began flashing while the car was parked. This would stop and begin again intermittently. Returned to the dealer and left the car for several days. Finally a switch was replaced and the problem ceased.
| Exterior Lighting problems | |
| Hazard Flashing Warning Light Unit problems | |
| Headlights problems |