The best way to find out for sure is to fill up as soon as the light comes on. Subtract that amount from the amount of fuel that the tank holds when full and the answer is how much fuel is left when the light comes on.
The Kill switch is located under the left side of the dashboard in a Sonata GLS.
I FOUND 1 JUST TO THE REAR LEFT OF TANK ON OUTSIDE , AND ALSO ONE UP BY THE FIRE WALL
17 Gallons give or take, the low fuel lights up when you have about 2 Gallons left
by the steering column, on the left side
Fuse # 8, Passenger compartment, located on drivers side behind lower crash pad. Small "door" in front of your left knee.
Left side of the fuel rail.
In the 2002 Hyundai Sonata the turn signal flasher is located on the driver side below the fuse box in the far left corner of the floor board
I have a 1999 Sonata, and my fuse panel is underneath dash on drivers side. It is to the left underneath dash, kind of hard to see, but easy to get to.
The 2000 Hyundai alternator is located on the left-hand side of the engine, near the front. You can trace the positive battery cable from the battery to the alternator.
My light comes on when I have about 3 gal. of fuel left.
by your left knee under the dash dave
the o2 sensor is located at the left side of the engine towards radiator and is the upper o2.