2004 kia optima cruise contol not working green on light turns on but cruise does not work checked brake lights not the problem

There are two switches on the brake pedal, one for brake light, and one that kicks out the cruise when you hit the brake. That switch is closed when depressed (ie; brake pedal is up) and opens when pedal is pushed away from the switch, (unlike the brake light switch which closes when the pedal is pushed). This means it must be positioned and adjusted correctly for cruise to work.

see what the code is most auto parts stores will scan it for free in hopes to sell parts some car the cruise will shut off when the check engine light is on

You need to have the codes checked. when you cycled the key , you were resetting the ECM. This didn't fix the problem. Get the codes and let me know. We can go from there. There are to many things to list that can shut down engines. And you don't need to buy expensive parts that you don't need.
Randy

Does your cruise control work? If not it is the brake light switch. It will be a small mechanical switch that will be activated when pushing down on the brake pedal. May need a new switch or just adjusting.

Check the space gap between the brake lever to the brake switch.

Also check the connector to the brake switch.

You have to look under the dash carefully.

These is not too much room under there.

Just ran you hand along the brake paddle.

Press the brake switch by hand and see is brake light go on.

Check all connectors for corrosion.

It sounds as if your brake light switch is bad, or, your brake pedal return spring isn't pulling the pedal back towards the seat.

First, just pull up on the brake pedal, opposite direction of when you are applying them & see if the lights go off. If yes, you'll need a new return spring. If not, then usually the switch mounted up above the pedal is defective & needs to be replaced.

I believe once that is corrected, the lights should work properly if your parking lights are working, as they both use the same circuit. If not, you'll have to do some testing of those wires & backtrack to the light switch.

The Brake light switch also can have the cruise control switch & other controls associated with it but not always, depending on the specific Model & Year & other options so testing it could require a wiring diagram, I've included a link that will give you the wiring colors for the brake light switch itself. Testing the wiring is the only way to determine any other condition that would be causing that to happen.

Here's the link for the wiring:
http://www.commandocaralarms.com/wiring/2003-2005/Kia/Optima/893.html

It shows the brake switch wires as GREEN.
Good Luck.

You can check to make sure that the taillights have a good ground. If at all possible try using a test light or multimeter at the light. Have someone step on the brake and see if you have positive voltage to the light. If you do then it could be a faulty ground. If you don't move closer to the brake switch or even test the brake switch.

Check the fuses for these items they could be blown.

If the air bag light is blinking count the blinks for the code. Example.. If the air bag light flashes once and then a short pause and then two blinks you would have a code 12. and so on. If it just stays on you will need to take it into a repair shop and get it checked. My best guess without looking at it would be that the clockspring is not working properly. Most of the time when the clockspring goes out other things stop working like the horn or cruise control or something that is on the steering wheel. Hope this helps.

make sure to check all the fuses and specially tmake sure your brakes lights works because they comuncate w/ cruise