Removing Factory radio

Look in the fuel pump/filter area?

Yes it's in the factory service manual available at the local dealer or online.

sound like dead battery,could have loose or broken alternator drive belt, if drive belt look okay,alternator could be faulty.

sound like dead battery,either alternator faulty or alternator drive belt could be loosen need adjusting or drive belt broken.

Here are the radio connector wiring colors and what they do.
2000 Kia Sephia Car Stereo Radio Wiring Diagram
Car Radio Constant 12V+ Wire: Blue/Red
Car Radio Ignition Switched 12V+ Wire: Blue/Black
Car Radio Ground Wire: Black
Car Stereo Illumination Wire: Red/Black
Left Front Speaker Wire (+): Black/Yellow
Left Front Speaker Wire (-): Blue/Orange
Right Front Speaker Wire (+): Blue/Green
Right Front Speaker Wire (-): Light Green
Left Rear Speaker Wire (+): Green/Red
Left Rear Speaker Wire (-): Green/Black
Right Rear Speaker Wire (+): Blue/White
Right Rear Speaker Wire (-): Red/Blue

real headache.I would call dealer ask if there are similar problems on other sephias (2000) if so what caused it.

pls. be more specific in describing the problem/ door panel means the complete door/ u mean u took off the whole door to install speakers? or just the door trimboard?

You have a loose connection at the harness at the back of the radio. Only 3 possible wires that could be loose its the ground wire, 12volt wire or the ignition wire. colors are usually red-ignition yellow-12volt black-ground. Make sure those wires are connected real good!! with tape or solder the wires together.

most the time the cigerette lighter fuse has blwon. that fuse goes for radio and probably int. light.some fuses feed other fuses so cig lighter fuse does not have a label that says radio. check all the fuses anytime you check for elect. problems

I have a 2000 kia sephia and you just take two screws behined the weel where the speedomitor is and pull slowly apart the plastic cover and then there are 4 srews to take it out un plug the wires to radio. Then you good.