12.4v to 15v is actually normal for the Cruze. 11.9v is low however. The Cruze uses a variable output alternator for fuel efficiency.Watch your voltage reading for a day or two in the instrument cluster. If you experience fluctuations, it is likely the cable. It was very evident to me that the voltage was not stable, even though it did not swing wildly, it would just creep up and down.
I was experiencing symptoms with my radar detector acting strange by restarting or falsing in strange ways. Escort told me it was likely due to low or unstable voltage. That was the first indication that I had a voltage issue. The next day the radio blanked and restarted. Read the posts about the negative battery cable issues.
I set my instrument cluster display to voltage and watched over the next two days as my voltage would vary anywhere from 11.9V to 15V. Finally got to the dealer, they replaced the negative battery cable and it has been a rock solid 14.4V since.