Common problem on the Sunfires.
There are splices in the main wiring harness under the hood,under the battery area that corrode.
You will probably need to remove the battery and tray to access the harness,open up the conduit and trace the wiring back until you see the splices.You will find at least one corroded.I'm thinking ,probably the blue wire.
Make sure you repair it properly using heat shrink to keep the moisture out.
GM parts dept has the correct repair kits available for this.