When I purchased my +4 I noticed a red flashing light at the side of SWMBO's seat, I found out it was the connector for a hard wired Ctek (and not the rare optional ejector seat for SWMBO as suggested by one sage), there are in fact three LED's, red, orange and green as a traffic light system to indicate battery condition.
It is certainly easy to plug in the charger/conditioner but the indication goes red quite quickly even after some good prolonged running or charge and the battery is fine.
This is a Ctek part and I would suggest it's use if hard wiring in.
Good luck and enjoy your car.
