Sounds like an issue with your Power Steering. Since there's more than one possible reason why this could be happening, you'll have to do some troubleshooting to figure out the cause of the problem.
The Kia Sedona does not have a power steering belt. The power steering pump is electronic and does not require a belt.
Any tips on changing the power steering pump on my kia sedona
The 2004 Kia Sedona OBD 2 port is under dash below steering column
help
I don't know precisely about the Sedona, but generally the button on top of the steering column activates the flashing hazard lights.
You can go to Autozone.com and it will give you directions.
There is a diagram under the related links.
Left side of the vehicle right beside the steering column
Down on the steering column behind a plastic shroud
How can you reset an ECU on a Kia Sedona
left side of the dash under the steering wheel
Where is the banck 1 kia sedona 2004