I told you before check 5 volt ref. if you can't , take it to a qualified repair shop . You probably shouldn't be trying to fix it anyway ,unless at least a dealer tech .
Newer cars usually have a starter relay.This will be in the under-hood fuse block. The link below will take you to the location of under-hood block and the starter relay in that block. I hope this helps. Good Luck!
Here's a youtube link to starter removal. It may not be your model of car, but the principle is the same:
How to replace starter on Chevrolet Silverado 1500 and other General...
And some general images to give you an idea:
2008 chevrolet starter removal Google Search
Disconnect the positive lead on the battery (bear in mind you may lose your radio code when you disconnect the battery). Follow that lead to the starter -
The starter will be located at the side of the engine block where it mates with the transmission.
Disconnect the electrical leads on the starter and the solenoid, which sits atop the starter.
Use a wrench or a socket to undo the bolts that hold the starter in place. There's usually 2 bolts but some vehicles may have three.
Remove the bolts and withdraw the starter
The most common cause of this is that the rotating electrical contact (referred to as the clockspring contact) under the steering wheel is defective, very common in all modern cars. You MUST DISARM THE AIR BAG SYSTEM BEFORE REMOVING THE THE STEERING WHEEL TO SERVICE THE CLOCK SPRING.