2005 chevy cobalt remote start

im trying to put a remote start on my 05 cobalt but the starter wire is in under the hood ,right under the fuse box,but the wire is only 16-18 guage and the wiring diagrams for the car says not to use that wire for remote start.where do i get my stater wire from???? my buddy works @ a car audio shop and he found a wire that starts the car but my problem now is when the 555L learns the resistence to the key,the r/s only works on the first try loses the resistence code on the second try (i think) and it wont start! starts for a second and shuts off. oh yeah on the 1st r/s the car runs no guages turn on no a/c,no radio ,no nothing and my dash info read out says power steering!!! can some one help me please !!! i(i did the door locks on the car and my friend did the rest)

this car automatically cranks when it sees the ingition powered up and the accessory power up and drop out. all you need to is make sure you have wires hooked up right.My rifle is my friend...