Engine wont turn over?

My CTS is having electrical problem, I try to start it and all it dose is click noise from the starter and sometimes it stops then u have to try to start again and it keeps on doing it, It will not crank the motor, starter is brand new and tested. The starter clicks like if the battery was low in charge but its actually not. The voltage is right at 12. If I keep on trying it sometimes it try's to crank the motor. I also replaced the ignition switch but its still the same thing. Now you might ask me how do I know its an electrical issue, because I can started it with no problem though the starter relay in the engine compartment fuse box, I have also swap the starter relay and still the same. I just make the relay make some contact and the starter kicks in and starts the engine with no problem as long as I have the ignition on with the key. It will run and drive. So the problem has to be between the relay and the ignition switch. Please send diagram or possible issue if someone could help me I would extremely appreciated it.

It's not a battery or an alternates issue I've already checked them n they are new. I can start the car with no jumpers all I have to do is make a bridge through the starter relay and it will start as many times as I need it.

I got the new cable even though I did not think it would work but I was wrong everything is great now. I love this site. Cost me $118.00 for the cable BTW

We have replaced the battery with a new Interstate Battery, we have replaced with a new starter and put a used transmission with 80000 miles in the car. It will power up when turned on, but will not crank. What can it be? Thanks