2001 cavalier security and maint light

five years ago my son and I installed a remote starter on his car. unfortunately we didn't use a wiring harness to connect to the ignition. the instructions stated to cut the ignition wire, measure the resistance and wire in a resistor so the car could start with out the key. the starter works fine but from the beginning the theft system light and the maintenance light stay on the whole time. I want to get rid of the car and disconnect the remote starter. the wire needs to be replaced that I cut. is it a single wire or part of a harness? is it fairly easy to replace? how expensive would it be to have a dealership do it? will replacing the wire make the lights go off? 2001 chevy cavalier 4 cylinder