Alternator/generator/regulator problems of the 2008 Cadillac CTS

My car won't hold a charge. I buy a new battery and the car says battery saver mode activated. The battery will be dead by morning or if I take it down the road the voltage will start dropping before I get home. When I say down the road I mean less then a 2 miles. After I turn my car off it won't start because the battery voltage will be to low. I've had the battery and alternator check both are fine. Checked to see if their might be lights left on, but nope not even the truck light. So I'm at my end with the car, it's a $30,000 car that I can't even drive. That's a lot of money for a yard ornament.

The contact owns a 2008 Cadillac Cts. The contact stated that there were several electrical failures, such as the turn signals failed to function and the middle console electric functions failed to illuminate. After several repairs, the failures continued. The contact had three batteries replaced and the alternator assembly replaced, but the failures continued. The vent controls also failed to function for the heater and air conditioner. The manufacturer stated that there were no recalls pertaining to the failures. The VIN was not available. The approximate failure mileage was 110,000.